You just need to turn location off, reboot the phone, then you can turn it back on. As was stated, there is an issue in 1.5 that keep stacking over time and it slows the phone down to a crawl. For people who do not reboot their phone often, they see the lag. This issue doesn't exist in 1.6 or 2.1, so when we get the upgrade to 2.1 you won't have the problem. Just de select all three locations for about 30 seconds, then you'll be fine. If it lags again, just repeat.