How do you delete apps from Lion's Launchpad?
Launchpad-Control is what you are looking for my friend. It's a free preference pane app that lets you uncheck what you want to hide. It even backs up for safety :)

Alternatively, you could enter the following into Terminal:

sqlite3 ~/Library/Application\ Support/Dock/*.db "DELETE from apps WHERE title='APP_NAME';" &amp;&amp; killall Dock

Replace the "APP_NAME" with the name of the app as it's displayed in Launchpad. 

To display it in Launchpad again, simply move it from Applications folder and then put it back.