how do i remove the belt tensioner and pulley on a 94 bonneville se?

Hi, this one'* a bit of a chore, but doesn't look too bad. I'll confirm with my manual when I get home, but here'* where to start.
1 - remove belt (maybe that'* already done for you?)
2 - remove alternator - 2 bolts only, plus battery cable nut and field connection (disconnect battery first!)
3 - remove power steering pump. It has two bolts, one above the shaft, the other below. Look through the holes in the pulley.
4 - looks like one additional bolt holds the rest of that tensioner assembly on, and it is below the PS pump, almost underneath and behind the tensioner pulley itself. So, you might need to hold it out of the way while you take that last bolt out.

If I find any differences 'in the book', I'll let you know.

Update:
Replace step 4 in the previous post:
4 - remove heater coolant tube (after draining coolant?) This part is held on with a small bolt at the point where it goes into the block or LIM (don't recall which), and a nut on a stud which must be removed to remove the tensioner bracket.
5 - remove the bolt (FSM shows stud) mentioned in step 4 in previous post
6 - remove stud and bolt approximately aligned vertically beneath the position of the PS pump. The upper (stud) was where the heater coolant tube bracket was attached.

You'll want to find a new o-ring to re-install the heater coolant tube. On my car, when I did my engine swap, I think I needed a new tube altogether!

I sure hope this helps!