See John Jakey's page for his links
http://staff.washington.edu/~jon/gnuradio.html

GNU Radio main page
http://www.gnu.org/software/gnuradio/
The starting point

GNU Radio Wiki
http://comsec.com/wiki
General information

GNU Radio Mailing list archives
http://lists.gnu.org/archive/html/discuss-gnuradio/
Search here first for all of your GR/USRP questions

GNU Radio Mailing List
http://www.gnu.org/software/gnuradio/mailinglists.html
Get on it ASAP! Very active. You'll learn a lot just by reading the daily activity.

Matt Ettus
http://www.ettus.com/
For all your USRP needs

Chuck Swiger
http://webpages.charter.net/cswiger/
Lots of good stuff. Many full applications and scripts.

kd7lmo
http://www.kd7lmo.net/ground_gnuradio_install.html
Ground station for high-altitude balooning
Installation scripts, OTA data captures

Dawei Shen
http://www.nd.edu/~dshen/GNU/
Excellent place to start.
Tutorials, tutorials, tutorials

Eric Blossom
http://www.comsec.com/software-radio.html
Not much GR stuff here. But, hey, he's the man.
Passive Radar
http://comsec.com/gnuradio-project-2006.html
http://events.ccc.de/congress/2005/fahrplan/attachments/673-slides-passive-radar.pdf&e=10401

Lee Patton
http://www.pattoncentral.org/?cat=11
Installation guide, and search plugin. Active radar.

David Carr
Rice University
http://oscar.dcarr.org/ssrp/
Simple Software Radio Peripheral

Krys Kamieniecki
http://kamieniecki.com/krys/gps/
Developing kkGPS, a pure software defined GPS receiver

Lamar Owen
http://www.lamarowen.net/pgallery/album?album_id=2060
Cool USRP Case

Jamey Sharp
http://svcs.cs.pdx.edu/trac/wifi/
Implementation of IEEE 802.11 nwtworking standards

imirkin
http://web.mit.edu/imirkin/www/gnuradio/bpsk.html 
BPSK and Costas Loop stuff

Prateek Mohan Dayal's Thesis
http://www.geocities.com/pmd_iitgw/thesis.pdf
Senior year thesis.
SOFTWARE BASED NTSC SIGNAL PROCESSING

John Jacky
http://staff.washington.edu/~jon/gr-osx/gr-osx.html
http://staff.washington.edu/~jon/gnuradio.html
Lots of stuff
GNUR Radio under OS X
Magnetic Resonance Force Microscopy
http://lists.gnu.org/archive/html/discuss-gnuradio/2005-01/msg00232.html
http://courses.washington.edu/goodall/MRFM/index.html

University of Paderborn
Holger von Malm, Stefan Valentin
http://typo3.cs.upb.de/en/research-group/research-group-computer-networks/projects/gsr.html
http://typo3.cs.uni-paderborn.de/fileadmin/Informatik/AG-Karl/Pubs/TR-RI-06-273-gnuradio_testbed.pdf
Complete transceiver chain including a simple PHY, the ALOHA MAC protocol and the send-and-wait ARQ running on GNU Software Radio.

University of Cape Town, Radar Remote Sensing Group
http://rrsg.ee.uct.ac.za/projects/softradar/
Software Defined Radio/Radar project

Martin Dudok van Heel (Dvh)
http://www.olifantasia.com/pub/projects/gnuradio/mdvh/passive_radar/
Passive Radar code
http://www.olifantasia.com/pub/projects/gnuradio/mdvh/mingw/binary-installer/gnuradio-with-usrp/
Windows version

Tracey
http://www.tracey.org/wjt/temp/gnuradio-wxapt/noaa-17-03260415-norm.jpg
Getting weather satellite feeds

Juan Domenech Fernandez
http://www.domenech.org/homebrew-sdr/receiver-1.htm
Is using GR, but don't see GR related posts

Larry Doolittle
http://recycle.lbl.gov/~ldoolitt/xguff.html
Xperimental Gnu USB FPGA Framework

MIT Viral Media Lab
Jamey Cooly
http://viral.media.mit.edu/wiki/tiki-view_blog.php?blogId=3
Install under Ubuntu
http://alumni.media.mit.edu/~jcooley/gr_experiments/
GNU Radio Experimeents

Department of Computer Science University of Illinois at Urbana-Champaign
http://srg.cs.uiuc.edu/swradio/
Security of Software Defined Radio

Department of Computer Science University of Illinois at Urbana-Champaign
Raquel L. Hill, Suvda Myagmar, Roy Campbell
http://choices.cs.uiuc.edu/~myagmar/hill_threat_wwc05.pdf
Threat Analysis of GNU Radio Software

NCSA
http://ner.ncsa.uiuc.edu/sdr/
Receiver

Josh Lackey
http://noether.uoregon.edu/~jl/gmsk/index.html
GMSK code

NCASSR (UIUC)
http://www.projects.ncassr.org/sdr/rf_samples/index.html
http://www.projects.ncassr.org/sdr/rf_samples/tvrfplots.html

NWACC
http://nexp.cs.pdx.edu/~sdr/
Home
https://projects.cecs.pdx.edu/~icarroll/SoftwareGPSCorrelator/
GPS Correlator

http://www.ecsl.cs.sunysb.edu/fir/
An Implementation of a FIR Filter on a GPU

http://www.ee.nmt.edu/~dbaird/ee446-project.pdf
FM Receiver project

Clark Pope
http://www.drs-ss.com/
doing 802.11b with DBS Rx

David Bennington
http://www.keystoneradio.com/grGPS.html#GPSAsics
GPS Receiver

NCSU
CSC-791V
Physical Layer Encryption of Wireless Communication Signals
http://www4.ncsu.edu/~kakandek/stuff/csc791v/practicalProblems.html

Greg Troxel, David Lapsley
BBN Technologies
http://lists.gnu.org/archive/html/discuss-gnuradio/2006-03/msg00421.html
http://www.informationweek.com/story/showArticle.jhtml?articleID=174907945
Cognitive radio networks

Vivek Raghunathan, BBN Tech.
ADROIT Project
getting GNU Radio to be able to receive and decode IEEE 802.11 frames 
and inject these frames into the NetBSD kernel networking stack.

Virginia Tech
http://www.vtnews.vt.edu/story.php?relyear=2005&itemno=995
Cognitive Radio
Interfacing USRP with OSSIE

UCLA
Tad Dreier
Graphical programming of GNU Radio w/ Ptolemy
http://www.ee.ucla.edu/~tjdreier/gnuradio_ptolemy.jpg

U. Michigan
Achilleas Anastasopoulos
http://www.eecs.umich.edu/~anastas/
Trellis coding

Chris (Robert) Roberts
Case Western Reserve Univ.
MATLAB/Simulink, GNU Radio/USRP laboratory exercises

Companies
---------------------
http://metricsystems.com/ (John Clark)
http://www.drs-ss.com/    (Clark Pope)
http://www.bbn.com/
Sensus Analytics/ Path Intelligence

Tom Rondeau
Virginia Tech
QPSK transceiver

Dr. R. Heath
Univ. of Texas
http://www.ece.utexas.edu/undergrad/464projects.html#gnu

PathIntelligence
http://www.pathintelligence.com/
Track pedestrians using GNU Radio / USRP

Naveen Manicka
Univ. of Deleware
http://www.cis.udel.edu/~manicka/Resume.html
Implementing a custom MAC protocol on a GNURadio-based network testbed

Schools using GR/USRP
----------------------
MIT
Case Western Reserve
Notre Dame
Portland State
NCSU
Wright State
Virginia Tech
UCLA
University of Michigan
Univ. Illinois at Urbana Champaign
Univ. Illinois at Chicago
Telematik, Techn. University Graz, Austria
Univ. of Texas
University of Utah (USRP developed under NSF grant there)
Univ. of Deleware

Agencies using/funding GR/USRP
----------------------
DARPA
AFRL
Radio Astronomy places
NASA AMES