There are different methods of overclocking, with one being extremely simple. A click of a button basically. That would be the automatic overclock most new motherboards provide. Can probably bump your CPU from 3.6 up to 4.2GHz. Pretty sure the mobo you chose has that going for it. Next would be a manual overclock that requires either the use of the mobo's software or, more reliably, the mobo's BIOS. Either way, overclocking is not at all difficult. Just needs a bit of reading and researching online. Plenty of guides to help. Another thing to note is that overclocking nowadays is pretty safe. Mostly a trial an error thing. If you go over what your components can handle, they'll just shut down. You set things back to default and keep on keeping on
As for the games, overclocking does help weak CPUs preform better, especially if the game is more CPU bound, like WoW/WildStar. But with the CPUs you chose, I doubt you'll need to OC them strictly for WoW/Wildstar. That said, imagine crowded areas in game where your FPS drops to the 30s or 40s, by overclocking the CPU you'll still dip, but you won't dip as low. Overclocking makes everything perform faster, the OS, games, load times, etc... But things that have hit their peak performance pre OC won't see much difference. Therefore, it's pretty pointless to overclock a PC that's only used for surfing, movies, word processing, etc... A PC used for gaming/other intensive tasks, however, every bit of extra performance is welcome.
My advice is, if you're not short on cash, get the unlocked CPU n its proper mobo. It's nice to have the option to OC should you ever crave it for some crazy reason. N like I said, overclocking is very easy. At the least you'll do the automatic 1 click overclock.