Testing tinyurl.com on Twitter updates

I’m tinkering with my MT-Twitter plugin. If this works, it should create a Twitter update with a tinyurl instead of a longer zuckervati.com url. In MT 4.x, the MT-Twitter plugin should automatically do this if the URL is longer than 30 characters, but:
a) I’m not using MT 4.x (although I’ve downloaded and am testing the open source MT 4.x)
b) I want this to shrink all the URLs to tiny format
Hopefully this will work, otherwise I’ll either have no Twitter update or something very crazy-looking.