LinkToApp.com

Link to iTunes Store Apps easily.
Try It:
http://linktoapp.com/
Usage:
http://linktoapp.com/appname
http://linktoapp.com/long+app+name
Examples:

Single words:

http://linktoapp.com/facebook
http://linktoapp.com/currency

Replace spaces with '+':

http://linktoapp.com/super+monkey+ball
http://linktoapp.com/cannon+challenge

If it can't find the exact app name, it will send you to iTunes search:

http://linktoapp.com/super+monkey
http://linktoapp.com/cannonchallenge
Bookmarklet

Drag this link to your browser's bookmark bar:

Link to App

You can then highlight the name of an app on the page and click on the bookmarklet and it will take you to the app.
Example: Super Monkey Ball
Tips

In messageboards, instant messaging, and twitter, this tool makes it
easier to quickly link to an app without looking it up in iTunes.

Need a shorter url? You can also use http://L2app.com
Normalkid, LLC