How to set a limit on iPhone Internet use?

Whenever I'm curious about something, I hop onto Safari and Google it. Pretty soon I'm Tweeting, checking Facebook, or replying to emails. And quick as a flash, there's another hour wasted.
If anyone could tell me how to set a time limit, I would really appreciate it.

I don't know about setting a TIME limit, but there's an option to set a limit for the amount of internet usage per month.
I have it on my phone. Just go to your phone carrier store and ask about it. I have t-mobile btw.
Hope this helped