yea i agree with Peachey. "already" in that tense would mean "now" or "quicky".. like someone is in a hurry or just don't want to be there anymore. As for Oz... you're right... We do us it in the Us ^^ .. A lot!

Yep, exactly what Peachey said. "Already" simply emphasizes the action being referred to with more force. It's not used in the UK. Definitely used in the US

Humm not exactly. You're thinking of "let's go already!", is that right? In this case, "already" has a closer meaning to "now", so "let's go already" is more imperative than "let's go". The hint is that time is being wasted, and there's a feeling of exasperation. Same as "let's go, alright?" and "let's go, OK!"