Bit Bucket means you can feed it a digital signal, and the recorder will basically save all those 0's and 1's. Also, you aren't using the recorders A>D when using a device as a Bit Bucket.
Cardioid and Omni are types of mics or capsules for mics. A Cardiod will pick up sound mostly from one direction (forward). An Omni will pick up from all directions, but you still should point an Omni microphone toward the sound source.
Binuaral is a technique using an Omni mic. Basically you put an object (frequently your head) between two Omni mics. This replicates the way YOU hear a sound. I think Binuaural should be used if you plan on listening with headphones, but I think it works fine for speakers as well. I only use Binuaral when I'm stealthing.
I live in Boulder. I have a show this Saturday at Albums on the Hill in Boulder, but I'm not 100% sure I'm taping (or if I'm even allowed to tape). After that I've got the Mark Vann Benefit at the Fox in Boulder (on 12/16, I think). I'm sure I will be taping that, and there will be plenty of other tapers. We're all pretty friendly (except Josh Simpson...he's a jerk...I kid, I kid).
You're certainly welcome to tag along, and I can show you the ropes. It's pretty easy.
I'd also suggest doing some reading over at Oade.com. A lot of good info there.
www.oade.comHere's the mic faq at Oade:
http://oade.com/Tapers_Section/faq-mic.html