I know it ain't the same thing, but I have just successfully compiled Freeswitch v1.0.5 and am now connecting my IP phones / XLite to the server. I originally got the idea from Linux Magazine, september '09.
I am using an eSata 'plug with a 1G drive attached. I only had one compilation error, using G++, which is probably due to the ARM implementation of the inbuilt structure 'va_list' as used in module 'sofia.c'. I already had some .xml configuration files for Freeswitch in a previous incarnation so copying these over has simplified installation. Now if I could remember what I set my phones passwords are......

So there is an alternative to Asterisk though since i have not used that, I cannot compare with freeswitch.
Modified to add:-
Two Cisco SPA921, one Snom 320, a Linksys PAP2T VoIP phones attached; several windows PC's using X-Lite, trunk connections to two external SIP providers active on the Sheevaplug. Traffic levels are very low but testing shows no server issues. I am considering adding the Skype module to Freeswitch which should improve inter-family connectivity. Lots of bells and whistles to add but the basic system works. I wish I could get a better internet connection but with no fibre and a significant distance from the serving exchange limits DSL bandwidth.