If you've no CD/DVD burner, .zip it with a password and rename the file to something obscure and then upload that.
I don't think that's a good idea. There is rar, zip password cracking software available and with todays PC power the password could be cracked.
Also, a person who could afford BlitzMax must be able to afford a CD Burner. You can pick them up for less than £30 these days.