Need to know more- are you getting rid of one Mac, are you wanting to sync stuff, what? Exactly what files do you want to try and sync if that is what you want to do. Only itunes and mail?
What OS are both Macs running? do you have a .Mac account?
please give us more info.
I use .Mac mail and store everything on the server and it copies it to my computer as well so I have it( and attachments) when I need it- even if I am not connected to the net. I am not running Tiger on both Macs though so can't use the sync mail stuff I don't think.
I don't know about iTunes though- I personally want to know the easiest way to get my purchased music from my home iMac to my iBook and have it keep the song titles and band names. I burned some cd's of my purchased music, but when I imported it to iBook it had no CCDB info.
I also use .Mac to sync my bookmarks, iCal, addressbook on three macs.