This may already have been pointed to in another thread somewhere, but I just ran across this site with instructions on how to set up WebDAV on your own computer (in Leopard), eliminating the need for MobileMe or another private server:
http://preview.tinyurl.com/5ox54c
Read down in the comments for info on doing the same thing in Tiger.
I have not followed the instructions, so I can't vouch for them, but I have done something similar in the past, so it should work.