Some similarities:
1. decentralized : there is no one Pope for either,
although there are certainly Ayatollah wannabes in OSS
like RMS.
2. imperialistic : just as muslim armies once attacked country
after country, and today there is a "reverse crusade" & jihad
happening, OSS is entering almost every area of software use
and many OSS partisans are going to an extra effort to
impose free software on their organizations, families, etc.
3. no dissent allowed : just as muslims feel compelled
to attack anyone who speaks blasphemy, such as Salman Rushdie
who merely points out that the koran is merely a historical
document (therefore he must be killed), so alas OSS
supporters become very angry when any dissenter speaks
their mind.
4. destructive : OSS radicals want to get rid of even
the copyright, and the GPL is written to strip software writers
of their rights over their work (read it...); similarly
muslim radicals want to rid the world of non-muslim people
and impose taxes and prison time or worse on non-muslims.
And surely there are more similarities.
This isn't to say that free software is all wrong,
but it is better to know and think about the movement
and whether it is going in the right direction
than to let it become evil, like islam. The copyright
for instance is so basic, to remove it would be so radical
as to be insane.