Working with both a PC and Mac

I have a Mac at home, and am using a PC at school in my programming class. Whenever I launch an Alice program on the Mac that was created on the PC, the File name is renamed to something like ._file.a2w instead of the original file.a2w (an ._ is added). This makes it so that Windows Explorer won't recognize it and Alice for Windows gives an error. When I bring the file back home, it launches fine in Leopard.

Any suggestions?