Are my internet searches saved to the phones internal memory? how long?

If you are on BES, probably saved within BES if the company/BES Admin so requires it to be. If you are on BIS, not likely.

hey im looking for a bit of info
if any of u know wat mxit is and a way to run it on
the bb7230 as i am able to run any other apps and it just refuses to work maby there is settings ofr somthing that will allow it to work
much appreciated

I dont believe that internet searches are save to the phone, but the pages that load are.
If you delete the cache, it will delete those pages.

And, worshe, dont hijack a thread to ask a new question. Its bad manners.