You can also use WinRAR, which can split a file into compressed pieces as big as you want them to be (you have to express the number of actual bytes, 1024 bytes being 1KB ect), but it will split the file up. WinRAR needs to be used by the downloader to put them together. The filenames for the pieces are usually either .rar, .r00, .r01, ect. or .part1.rar, .part2.rar, .part3.rar, ect. WinRAR knows how to deal with both kinds.