Is there a formula (or a downloadable program) for calcutating tempos based on time and number of measures? I don't have a midi sequencer. I know the number of measures and time it needs to fit into. How would I calculate the tempo from that?

If I understand you question correcly, all you need is a calculator. I have never done this, but it should work this way:
1) Calculate the number of measures per minute.
2) Multiply that number by the time signature. ( X 4 for 4/4 time, X 3 for 3/4 time) = beats per minute (tempo)
Starkeeper

that works great if you're cue is exactly in 1 minute incements. But what if it is 2.6 minutes, and 45 meaures. There must be a way to incorporate the duration into the formula. Obviously, I'm not a math wiz.

2.6 minutes = 45 measures
1 minute = 45/2.6 = 17.3 measures
17.3 measures X 4 (assuming 4/4 time signature) = 69 beats per minute.
tempo - 69bpm
If your listening to a song and want to get the tempo, why not try to increase or decrease the tempo on your arranger till the beats sync up closely?
Starkeeper