How the heck do I get those things off.. lol I can't get a socket around it, and I can't get a wrench in there. Grr
You will need to get a O2 sensor socket. It looks like a crows foot socket but closes up the openning like a flare nut wrench. Hard to describe. There is also the type that looks like a deep socket with a slot cut up one side, allowing the wiring to pass through. Also spray it with a lot of penetrating oil. Yours looks pretty crusty.