Krun.ch is an online compression and email tool that allows you to submit up to 10 files into an archive (up to 10mb) which can then be sent to an email address.
This is of questionable value; after all, pretty much every machine has archiving software installed, so you could easily create an archive locally and send it via yousendit.com. This strategy has the benefit of allowing you to send files up to 100mb for free. Krun.ch is certainly worthy of investigation though, and if the feature-set evolves it may prove to be a contender in the crowded file sending and sharing market.