No, that's fine that you haven't seen the terms and acronyms before. Looking back through it, here's what I saw:

FTP = functional threshold power, which highest possible average power for about an hour, assuming you went into it fully recovered. This might be the power you could produce for a state time trial or a big 60' hill climb race.
AT = aerobic threshold (usually heart rate at FTP)
LT = lactate threshold (casually used interchangeably with AT)

Interval workouts are described as repeitions x work duration x recovery duration. So, 6 x 1 x 5 would be six one-minute intervals with five minutes of recovery.

Three minutes can be expressed as "3 minutes," "3 min.," "or 3' "

Power is measured with a power meter. Most everyone around here who has a power meter has either a PowerTap, an SRM, or a Quarq.

Hope that helps. Lurk the training status thread for a while to get a feel for what people are doing.