Thanks. The seller responded and confirmed it was the UK Toggle and also that it's a dual Standard SIM/Micro SIM. So, I just have to pop out the Micro SIM portion and put it in my tray and pop it in my phone.
Once I get it, I'll worry about seeing if I can get it all setup and running with a UK number from the USA. Dunno if I really NEED a local US number with it too, but why not? Just to try it out quickly. As far as data, if I get a 500 MB one, I think I'll be OK just based on usage patters in the past when I am out and about all day. I already have it set to NOT auto download app updates. I do have other things always on like email and what not. But with 500 MB, I won't blow through it. At least, while in London. When I get to Paris, it will be a different story. I'll have to be careful there. Probably turn off email syncing and Facebook notices and stuff. And maybe just keep the phone OFF or in airplane mode until I need to do a quick foursquare checkin or Facebook update or use Google Maps