I had an issue with an application that couldn't be updated, and solved it by uninstalling the market updates (maybe there was another method, but in my case it worked). Problem is, now I can't find a way to reapply the market updates. Before uninstalling them, the updates were applied automatically, but now half a day has passed and I still have the version that came with the phone.
Edit: In case it matters, the phone is a rooted Samsung Galaxy Ace, running the latest official firmware (2.3.4)