The latest security update from Apple broke ssh for me and, apparently, many others:
mark@dijkstra:~$ ssh
Bus error
Update:
Looks like this is due to an incompatibility with Instant Hijack from Rogue Amoeba. Disabling this software restores ssh functionality. Thanks to Adrian for pointing this out.
Update #2:
As if there was any doubt that Rogue Amoeba was awesome, they have already fixed this in AirFoil 3.1.3. Quoting the site:
Updated Instant Hijack to 2.0.3 - fixes a crash in ssh and related commands when using Mac OS X 10.5 (Leopard) with Apple Security Update 2008-002
Update #3:
Full details on the fix are available on Rogue Amoeba’s blog here. Thanks for the link, Paul.

Check out http://tinyurl.com/3bo65u for a fix, it seems that the problem was found. Cheers!
Awesome. This worked! Thanks!
Please see this link for full details:
http://www.rogueamoeba.com/utm/2008/03/19/security-update-2008-002-compatibility-fix/
Thanks Paul!
The turn around time on this has my head spinning. Awesome customer service.