Hey Nick,
Not being a gamer yourself I would suggest you find some gaming forums and just start reading through them. You may come up with some great ideas and you also may be able to recruit someone to fill in some content for you. You can always hire someone to write articles for you. If you type "article writing" in google there are tons of resources. There are also other web forums on which you can place a post looking for someone to write them for you.
I know pretty much nothing about gaming either but my 14 year old is constantly looking up cheats on the net so I would think, depending on your target audience, that would be a definite plus to have available.
Another option is maybe trying to find someone else with a ps3 site and some type of trade-off to share content? I don't know, just throwing ideas out there...
A buyer/seller site may work well but there are loads of them out there. On the other hand, there has to be a reason there are so many, eh?

Hope that helps.