This tool lets you generate 42 different types of hashes including the popular md5 and sha series (sha-1 through to sha-512). If you want to use a salt then simply include it along with the message.
This tool uses PHP to generate the hashes (with ajax to make the requests quicker). The PHP code is really simple and is as follows:
Simply change md5 with the hashing algorithm you want and alter false to true depending upon whether or not you want the output to be binary.
hash('md5', 'your message', false);