Help formatting a UTC TImestamp

[Guy Baumann]

I am trying to format a timestamp from an api.  It is the format 
"2011-03-24T20:30:47Z"

what I want to produce is something like this
(strftime "%d %b %g " (localtime (current-time)) )

However I am unable to work out how to do this, have tried using string->date 
with results below

Enter `,help' for help.
scheme@(guile-user)> (define date "2011-03-24T20:30:47Z")
scheme@(guile-user)> (use-modules (srfi srfi-19))
scheme@(guile-user)> (string->date "~Y-m-dT~H:~M:SZ" date)
srfi/srfi-19.scm:1415:18: In procedure priv:string->date:
srfi/srfi-19.scm:1415:18: In procedure string->date: TIME-ERROR type 
bad-date-format-string: "2011-03-24T20:30:47Z"

Entering a new prompt.  Type `,bt' for a backtrace or `,q' to continue.
scheme@(guile-user) [1]> (string->date date "~Y-m-dT~H:~M:SZ")
srfi/srfi-19.scm:1415:18: In procedure priv:string->date:
srfi/srfi-19.scm:1415:18: In procedure string->date: TIME-ERROR type 
bad-date-format-string: "~Y-m-dT~H:~M:SZ"

Entering a new prompt.  Type `,bt' for a backtrace or `,q' to continue.
scheme@(guile-user) [2]> (string->date date "~Y-m-dT~H:~M:SZ")
srfi/srfi-19.scm:1415:18: In procedure priv:string->date:
srfi/srfi-19.scm:1415:18: In procedure string->date: TIME-ERROR type 
bad-date-format-string: "~Y-m-dT~H:~M:SZ"

Entering a new prompt.  Type `,bt' for a backtrace or `,q' to continue.
scheme@(guile-user) [3]> (string->date "2000" "~Y")
srfi/srfi-19.scm:571:22: In procedure encode-julian-day-number:
srfi/srfi-19.scm:571:22: In procedure -: Wrong type: #f

thanks for any help

//guy