Activate XP SP2?

So I'm going to format this HD with XP in it, and reinstall XPSP2 later. However, I've read on some sites (thanks to Google) that the famous THMPV key is not anymore being accepted by Windows. Is this true? If so, how can I activate it then?

tl;dr how do you pirate your Windows, /comp/?

Use linux and/or pay for the damn software.