FreeBSD 6.1 max sockets

[ke han]

I am writing a socket server deamon in C++ on FreeBSD 6.1 (or 6.2 if  
this matters to your answer).  What this does is accept many sockets  
and does a little work with each.  Each socket has low traffic but  
stay connected for long periods.  All these sockets get accepted  
through one public ip:port (if this matters).
So my desire is two things:
1 - good event handling for knowing which sockets have new data.  I  
assume kqueue is the way to go here?
2 - I need to know what my limits are on max number of sockets.  If  
my system is a 64-bit install on a server with 8GB RAM, I need to  
know how many sockets I can handle.  Also, what options do I have to  
tune this?  socket buffer size?  Any kernel parameters needed to tune?

thanks, ke han