Rarhost and Krunch
Rarhost is a file hosting site just for rar file format only. Rarhost is now open for free membership.
And for online file compression, see Krunch, where you can upload up to 10 files and compress them online; upload a compressed file and decompress it online; view or download the file contents; fetch files from the web, compress them into a single archive, and then later decompress it online.
Original post by David Ledbetter