Networking between Ubuntu and MacOS X

[Matthew S-H]

I want to mount my Ubuntu hd (formatted as ext3) on my mac, and I 
wanted to mount my Mac hd (formatted as hfs+) on my Ubuntu machine.  
Both should preferably be read-only, and they must auto-mount at 
boot/login time.

I was wondering what the best way to do this was.

Oh, and btw:   They are networked by a wireless LAN.  Both are 
definitely connected properly to the LAN, as they can both surf the 
web, and I have the IP addresses for both.

Thanks for your help :).

~Matt