Addendum 1:
(for OSX-users?) although
http://www.yousendit.com/ says it can handle files/zip-archives up to 1GB, only files/zip-archives UNDER 150MB got through sofar in my tests using Safari and InternetExplorer.
FireFox, however, DID deliver my testfiles of upto 671MB!
Addendum 2:
if your connection is severed during one of those long uploads, don't despair. Simply re-establish your connection and click yousendit's upload window to reactivate the upload. Although that may take up to 10 minutes, the upload WILL resume and pick up exactly where it left off.
Hey, Windows-users: feel free to add your own experiences with
http://www.yousendit.com/ here. Your brethren may appreciate it.