URL field lengths

Im trying to enter a URL in a URL field that is longer than 255 chars (see below) but come up with an error when submitting. Is there a way to increase the size of such a field? I dont see an option for it in the Field options?

Thanks.

http://www.microsoft.com/downloads/details.aspx?FamilyId=8fc8340b-c2b3-4559-835c-caa00cf086b9&displaylang=en