On the SocialGeek blog there's a recent post that looks at making stubs for your URLs, making them easier to read and remember.

This is where the fun begins of course. How many times have you been confronted with someone sending you an indecipherable, thus untrustworthy link? Right, so we agree that for a user, it is important to have a clean URL that is readable and includes the title of the page or (at least) some description related to the content. Slug time!

They explain what slugs are (and how they're useful for users) as well as how to convert a title into a "slugged" string by replacing anything that's not an A-Z or 0-9 character to remove the less URL friendly characters.