How to remove an app from my iPhone (freeing memory) but keep it in iTunes?

I have a couple of apps that I have rarely used and which not only are HUGE (taking lots of memory) but also get frequent and large updates. (Almost every time I download app updates at least one of these apps has an update, and it's usually as big as All the other updates combined and takes 20 minutes or longer.)

I'm also seriously cramped for memory in the phone, so I'd really like to remove these apps from my phone. It's very possible that I will never want to use these apps again, but then again I might. And I paid for them so I don't want to totally remove them from iTunes (and have to buy them again if I decide I do want to use them.) So how do I free the space on the phone and eliminate the maintenance overhead, but not give up the prerogative of using them in the future?

Details:
iPhone 4 16GB
iOS 5.1.1
iTunes 10.6.3.25

If you bought them on an account, they will forever be free to that account. In a sense it saved to your I tunes library yes.

Sync with itunes, then you can delete it on your iPhone by pressing your finger on the app and click the ''X'' button. The app will stay on your computer even if you remove the app from the iphone if you synced it at least one time.

You can still sync after that without having the apps and not losing it.