If you can get a copy of Norton Ghost, I think this would be the easiest way to do this. If you can't get a copy of Ghost, then there are some free alternatives but I'm not sure what they are - I'm sure somebody else will tell you though (or a quick google or even search of the forums here).
What Ghost and these other software programs would do is essentially take a "snapshot" of what's on one hard drive and make the other hard drive have the exact same "snapshot" of data. So you would shut down with one hard drive, "copy" that drive to the new one, change your jumpers and cables, then boot up on the new hard drive and still have the exact same software and everything.
Once you figure out what software you're going to use, be sure to ask more questions to make sure you don't goof it up - would suck to lose everything you have (I'm assuming you're like 95% of other users and don't back up

).