hey...the amiga can talk to your xp very easily with
http://www.amigaforever.com/ae/
this would be the easiest way in my opinion to transfer..use the xp box as a sort of share folder for the ibook and amiga
http://docs.info.apple.com/article.html?artnum=106471
of course you could also set up an ftp server on the mac...
but yea