The main thing you can do is flash a custom rom. FYI, rooting itself doesn't give you better battery life, you need to do tweaks which you can do with apps once you're rooted.
In the way of roms, I really like Cyanogenmod7 but probably you'd want to stick with Liberty, another great rom, because you're newer to this whole thing! There are several great apps that you can edit your lockscreen with, three in particular are Widgetlocker, Lockgo, Flyscreen. I've never done this because I've had a reason and I have cyanogen! There are lots of good instructions online about how to use them.
Have fun with your rooted phone! dancedroid You'll never want to go back to stock! (at least I dont!) ;-)