Help me with my unlocked iphone 3g?

I have a unlocked iphone 3g running on 2.1 firmware and im thinking about upgrading to the new 3.0 software. My iphone lags alot lately and when i open apps they close, like when i open aim and it loads blank and then goes home, i havnt even been receiving text alerts for when i get a new im. If i was to upgrade to the 3.0 would this stop?