Maps has become useless on 3G iPhone

This could go in the apps forum or in the 3G forum, so Im putting it here.
At this point, the Maps app is useless thanks to the iOS issues on my barely-one-year-old phone. It takes forever to launch, and the app hangs while the GPS is trying to locate me, regardless of whether Im using wireless or the cellular network. Attempting to enter a location to search for is an exercise in frustration as I wait upwards of 30-60 seconds for taps to be recognized, and half the time the app hangs after I get just a couple of characters entered.
This has happened immediately after two hard re-starts, after freeing up memory using the Free Memory app, with no pages loaded in Safari, etc. etc.
Last night a friend and I got totally lost in downtown San Francisco and nearly missed the curtain of a show we were attending because for 15 minutes, Maps sat there and refused to even show us where we were at that moment, never mind find where we were trying to go.
MacBook 15" Mac OS X (10.6.5) iPhone 3G iOS 4.2