From Zach Scrivena:
Simple command-line file splitter. Split a (binary) file into a specified number of slices, or slices of a specified size. Output files are automatically numbered, and can be easily concatenated (using "copy" or "cat") to recover the original file. Slice supports large files over 4 GB. Free software written in C. Version 0.2 improved command-line interface; general code clean-up.