Dave Weiner over at scripting.com has been doing a lot of work lately on URL shortening services. The problem is that if one of them goes down a large number of links go dead. His solution is that you have to own your own short names.
Having the short URL for my own links would solve that problem, but at the expense of having to set up a 301 redirect for every hit to it, pointing to the corresponding long URL. My URLs are pretty long after the domain anyway, so it's not really saving that much.
My site isn't really conducive to reading on a phone anyway, unless you've got enough screen space to be using email instead of SMS anyway, so I'm not terribly worried about the short URLs.
Bottom line is I can say "cook like your grandmother dot com" and people get it right. "see el why gee em" won't stick more than 30 seconds for most people.