These people seem to have little experience with dual core Pentium's (its not surprising to be honest they came out at a bad time with the Core2Duo hitting and competing against the superior Athlon 64)
But to be honest even an old Pentium D805 once OCed could play any game out these days, people telling you that it can't play games are under the impression that games are CPU constrained (99% of them are not) while a single core anything will hold you back and a stock speed Pentium D will probably be somewhat of a bottle neck once you OC them they can do just fine. Yeah you may get a few more FPS if your running an i5 or i7 VS an old Pentium D but thats buying a whole new rig VS OCing your old one and popping in a video card.
For proof just check the minimum requirement's for even something like Far Cry 2
http://www.bit-tech.net/news/gaming/2008/08/08/far-cry-2-specs-revealed/1
Your machines CPU is listed directly in the minimum spec with no OCing. Throw a nice OC on that thing and it will do quite nicely. Now typically the minimum specs on a game are a joke but I find the CPU one is usually less important then the rest of the numbers (RAM and Video card being even more important)
On a more important note the OP asked about OCing a rig, not "Should I buy a new computer?" Anything beyond that is not helping the OP with his question.
I would answer to the best of my ability even if some one came in here and asked how to OC a 440BX chipset
Merry Christmas everyone !!!