How do I know when updates are available for my phone?
To check for phone updates, go into Applications > Settings > About Phone and tap System updates or check for updates. However, if a new update comes out, then you should get a notification informing you so and giving you update instructions. If you root your phone, then you could install unofficial updates that are not from T-Mobile. There are instructions at http://forums.androidcentral.com/t-mobile-optimus-t/43138-how-root-lg-optimus-t.html if you want to do so.