Ok so you either have a brand new shiny android phone, or you've had it for awhile and want to know what else your phone can do. It used to be that rooting your phone would take a couple hours and there was some guess work along with some blind spots. Then some very good developers narrowed it down to no blind or unknowns and a half hour. The day has finally come so that everyone can root without a hitch and in no time at all. No guessing no unknowns no computer.
Using your phone open the market, search for 4shared, its free. Also download a file manager I use astro its free and also comes with an application backup tool. Download, install and open. Search for "z4root.apk" with out the quotes. Make sure you allow applica,tions to be installed from "unknown sources" open your file manager and go to your downloads file find z4root click it select open using application installation. Let the install run then after it is complete reboot your phone. Once your phone reboots open z4root. Press the root option. Don't worry if something goes wrong you can unroot and your carrier wont know that you have rooted and unrooted as long as you uninstall z4root before giving your phone to them. Once rooted you will have some new applications you couldn't have while running stock like super user. Make sure you have it. Once you have confirmed you have it you are officially rooted! :D congratulations!!!
Ok now what? Now lets get you your first custom rom. Wait what's a rom you ask? Go to android forums and do a little research. ROMS is what sets your phone apart from stock users. ROMS will give you wifi tether and custom kernels that can let you overclock your phones processor, you can change the look and feel of your phone, even run the latest android updates before your cellular provider even gets them. Open the market and search for rom manager download and install. Then open your 4shared app and search for rom manager premium.apk download and install next search for temp monitor.apk and overclock.apk. you are well on your way to rooted heaven. Open rom manager install the recovery option, this lets you change and backup ROMS. This is where you can unlock hidden features, depending on the rom you choose. Some of the devs have screen shots of the ROMS some do not, for the ROMS that don't have screen shots visit android forums and you can usually find screen shots of all the ROMS there.