I think it is already reduced automatically by twitter itself. Anyway, I'm not so
sure. Please let me try.

I guess that Twitter's official policy is "However, if you paste in a link that is
less than 30 characters, we'll post it in its entirety.  If it's longer than 30
characters, we'll convert it to a tiny URL."

So you want it to use tinurl for every URLs? 

Well, taking into consideration that Twitter already shortens them, maybe it's not
necessary, but it might be nice to have an option to shorten all URLs (if the user
decides that he/she wants it).
Or, another (more complex) option would be to sense if a message containing a URL is
over the 140 character limit and pop up a dialog box asking if you wanted to shorten
the URL.

There's more to URL shortening that the convenience, especially if you're a bit.ly or
tr.im user.

> It would be nice to integrate a service such 
> as snipr or tinyurl to reduce
> message length

and on receiving message decode them to the
full link.

From some time to now some of my twits are not updated -maybe (direct|silent)ly
dropped by twitter.com- without trying to short the URI's. I need to do by hand. This
suggest to me twitter delegates the shortening work to the client app.

I suggest mb-purple to short itself maybe using a randomly/round-robin picked
shortening service. And maybe letting the user to choose her favorite service through
the advance properties menu.