Rooting the phone basically is taking off the phones "stock" operating system and replacing it with an "aftermarket" one. It allows you to have more control over what's on your phone, and what your phone does. It also unlocks features that your service provider doesn't want you to have (like the free wifi hotspot on the EVO, etc)
Overclocking, is basically "tuning" your phone. Like a Powercommander does to our bikes, overclocking is getting the most out of your phone's processor.
Roms are the custom operating systems you install when you root.
Make sense?
And yes, those other apps like Blockbuster, etc came with the new update, but most importantly with the new update came SWYPE keyboard. Try it out, its freakin sweet!!!
Thank you very much, I going to get ride of the old samsung hue and get a real phone in the next few weeks and am trying to learn all about them.