Using SSD and HDD in same computer

You have options.

1. Intel SRT(Intel Z68 and newer only, sorry it does not work on AMD without other software)
This installs EVERYTHING onto the hard drive and only your most often accessed stuff get kept in a 64gigabyte(the last 64 can be used for other stuff or left as over provisioning) SSD cache. I has the advantage of being automatic and learning what you use often to keep those tasks faster. It also has the down side of being only 64gigabytes and you have no actual control.

2. HDD boot and SSD games. This is generally not the recommended config, but does allow any games on the SSD to load faster. It is important to know that many online games make you wait for other players anyway so it is not always better. You may load first, but be waiting on the last players to load. If you are playing lets say SC2, you are waiting for all players to load either way.

3. SSD for Windows and your most demanding games(SWTOR/GW2 get a decent boost from SSD's while games like Just Cause 2 gets no boost and loads fast on a HDD too). This is the most common way to do it.
You install windows to the SSD then move as much of your files(docs/desktop/ect) to the hard drive(using the Location tab on special folders). You can also install the less demanding games on the hard drive(just make a folder like games and install them into it).
You get SSD speed for most every day tasks and the games you choose.

For slightly more advanced users, you can move your files to the hard drive using this method.
lifehacker.com/5467758/move-the-users-directory-in-windows-7

You can also move games from the SSD to the hard drive if you are not playing then, but do not want to uninstall and reinstall them over and over. using mklink you can make windows see the game as still on the SSD while it is actually on the hard drive. Want more info on that, just ask.

Hope this gives you a start.