Possible Duplicate:
php short hash
MD5 hashes are long and inconvenient to use. How can I further encode a md5 string to produce a shorter string using a subset of characters, for example a-z, A-Z and 0-9? jsfiddle.net is doing something like this on their website to produce short links easy to copy and paste and look like this: http://jsfiddle.net/uY7Pk/