Twin express is a shareware transfer program, or you can use FTP or terminal transfer with hyperterminal, or you can use Cross dos to transfer stuff that fits on a 720k MS-Dos formatted disk.
Basically theres plenty of ways to transfer for free, but you can find out all the info needed by looking back through the archives here. Amiga Explorer is a commercial program, and the easiest to use - it comes free with Amiga Forever, which you can buy from
www.AmigaForever.com ;-)