Salam everyone,
This is a great article on the many differences (and similarities) between FreeBSD and Linux. FreeBSD 5.3 (stable) just came out a few days ago, I haven't had a chance to try it but I highly recommend it.
Also just in case you're wondering, FreeBSD has a linux emu so you can run a lot of Linux based apps, although there are limitations (namely linux binaries with kernel hooks).
Youssuf
Debian GNU/NetBSD
Porting Debian to the NetBSD kernel :
Gentoo Free/OpenBSD
Porting Gentoo to Free/OpenBSD.
One thing I *wish* they would port over to Linux is the bloody amazing PF (packet filter). Anyone here who has ever used PF will know that it is superior to Netfilters firewall/NAT package. I don't mean to cause any fights but I'm talking about serving a network of 20 boxes on a 486 DX/2 66mhz, 32MB RAM with sshd,httpd and ftpd running for those 20 boxes all with low memory/cpu footprint.
Later,
Youssuf
FreeBSD LiveCD
For those interested in a FreeBSD liveCD:
Scripts for generating your own FreeBSD liveCD
Youssuf