New HDD for Raid, Need some help?

Ok guys, I am looking to buy a 1TB caviar blue or even black WD drive, to give me greater storage and boost my speed a little, I was wondering if I will be able to RAID it with my 500GB Caviar Blue?

And what configuration will I need to gain a speed boost? where do I put my OS/Programs/Games/files?

Is RAID as simple as plugging in a second HDD? Or do I need special Hardware/software?

Thanks in advance guys