Going by what others are saying, these issues started with the last update. I. . .can't pinpoint when they started since there was like a month period there where there was no reason to turn on the PS3.
Every time I turn my PS3 on, and it logs into PSN, it rapes the fuck out of my network. Anyone on MSN or AIM can see me logging in and out right now, because sony has taken a shit inside my router. IP assignments are all fucked up. I can't tell what Sony's POS is doing because, puzzlingly, I can't access my router while the PS3 is turned on. It's at least doing something with IP assignment, since when I turn the PS3 off, and I can access my router, that's where the damage has been done. I keep a pretty tight leash on IP addresses on my network. I have a lot of machines, and each of them having a permanent internal address helps when it comes to troubleshooting.
When I turn the PS3 on, all hell breaks loose. Everything on my network disconnects momentarily, and logs back on in a slightly fucked up way. For example, this time, once Sony's dong stopped fucking my network, I have discovered that NONE of the devices on my network have the addresses I assigned to them. It appears that Sony's precious ShitStation 3 had its eye on a specific address and JENGARAPED the devices on my network until it got what it wanted. And then it didn't bother cleaning up after I shut the system off.
The solution? Well, same thing I always have to do after playing a PS3 game these days: cycle the fucking router. My router is trying to assign the SAME FUCKING IP ADDRESS to my MBP and my desktop PC, so I have shut down the MBP until I figure things out, allowing me to use my desktop unbothered. Then the random network behaviour starts. Minutes 1 to 5, I can access IRC and Messenger, but not HTTP. 5 to 10, you get HTTP now, but no Messenger, oh and IRC, but with no reliability. Every couple of minutes some network service becomes unavailable. This behaviour is always associated with post-PS3 use.
I'm not turning on Sony's garbage machine until they fix this shit. You want to know why XBL is worth 50 bucks a year? Because at least competent people are working on the network.