Having the same problem with WiFinder... Already had the app, and purchased a game via the App Store. The App Store showed an update for WiFinder, andint's been "installing" ever since (several hours, now). As a result, everything is VERY sluggish, and the battery is now nearly dead (was fully charged this morning)...
Hopefully, a sync with iTunes tonight will fix it, but the battery will surely be dead before I can get home
Edit: meant to add, this was done via 3G. Did you also perform your update over the air, or in iTunes?