Anyone else having problems with PSN logging out for no reason?

that is my problem too

nope. i'm sure if you call sony they'll be there to help you out.

i bought new router hasnt had a problem yet

Yeah, I get this whenever I use a wireless connection - but that's to be expected because my router/ISP is a piece of crap.

Works fine when I use a wired connection though.

Your router can make a difference. I've had LinkSys and Belkin, and both were varying degrees of steaming piles. I'm using a Cradlepoint right now, and it is quite awesome (besides giving me the option of Cable/DSL and/or Cellular).

However, the really BIG problem is your ISP. Especially if it's Cable (TWC, in my case; I've seen a friend 2 cities away also with TWC have the same issue). The DNS servers your ISP uses have to be stable. I've read online that the PS3 cannot really utilize (autoswitch to) the secondary DNS for PSN.

The best solution is to use OpenDNS (www.OpenDNS.com). All you have to do is use their DNS servernames (optional to sign-up an account with them) for FREE. They are sponsored by some big-name router companies, so I imagine that the industry has realized the problem with ISP's either intentionally or unintentionally giving poor DNS service.

Anyway, I started having severe problems in April 2009 with this; I switched to OpenDNS. Then, in May, my Belkin took a nose dive. (So, frequent PSN drops COULD be your router on its last legs.) But, my friend who did not have a bad router also switched to DNS and it also solved his problems.

I RARELY have 'random drops' from PSN anymore (even if I'm running more than 1 PS3 simultaneously).