Hi Matt,
The problem is for most dbs you can only go up to 255 chars for a varchar column so I would have to change to text field to make all dbs work with longer urls. MS SQL 2005 does allow bigger varchar columns but then I would lose backward compatibility with MS SQL 2000 unless I change it to a text field. I "may" change to text field there at some point to try and solve this, but one workaround you might try is using TinyUrl or Shrinkster to shrink the big urls as mentioned in this blog post.
Best,
Joe