Make A Shorter Link claims my URLs aren't valid

Mostly Make A Shorter Link only expects to see characters permitted by RFC 2396 in URLs. If this becomes a problem, its URL parser can be loosened up to accept invalid characters.
Contact us specifying the URL and we'll check it out for you.
Make A Shorter Link will only make shorter links for HTTP and HTTPS URLs. Make sure that you fully specify your URL including the scheme, e.g. put
http://www.thisisalongurl.com/way/too/much/information/for/an/email.html
rather than
www.thisisalongurl.com/way/too/much/information/for/an/email.html

Make A Shorter Link says there is a problem with my Key

If you follow a MakeAShorterLink.com link, and discover that the key is either invalid or not found, then it's likely that the link has been mangled somewhere between its creation and your browser.
If you received the link in an email, check that it hasn't been broken across two lines. If you entered the link by hand, make sure that you didn't mistype it. A Make A Shorter Link Key should look like this: http://makeashorterlink.com/?A5572333, with at least 8 letters or numbers following the "?".
If you're sure that the key ought to work, then Contact us specifying the link and we'll check it out for you.
http://www.makeashorterlink.com/

noch besser

http://snipurl.com/