I think we've all been there. It's a very addictive game. We have a medical term for it. It's called Just One More Turn Syndrome.well i was up till 3am playing last night ;( game should have a health warning with it lol.

Yes, it is. One small caution on armies. The other really huge thing about armies is the extra movement. They have movement equal to that of the slowest unit +1. So don't add an infantry to a cav army. A cav army has a movement of 4 (cav (3) +1). If you add another cav or Modern Armor (both 3-move units), the army stays a 4-move unit. OTOH, if you add an infantry, it becomes a 2 move army (infantry (1) +1).Anyway game should be won by domination now as two more opponents are down... largely due to VMxA pointing out i can build armies with MT...multiple attacks is a HUGE thing really.
Once you get the the MA and the Pentagon built, you should be fielding 4-unit cav armies, and be able to take down your opponents pretty quickly. Good luck and let us know how it turns out.
I don't know what the costs are for those upgrades, but by that point in the game, I usually don't upgrade a whole lot of defensive units. I've used guerrillas and TOW, but I don't tend to use either extensively. I'm much more interested in attackers.Ow and Aabraxan yeah guerillas seemed very dissapointing...civpedia states A:6 D:6 but i swear they are lower... but i thought guerilla-> tow infantry was a good deal?
Also, somewhere around here, we've got a pdf reference sheet that shows all of the units, their requirements, costs, and upgrades. I found it very handy to keep that sheet at hand when I was first playing. You can get it in the Reference Section: http://www.civfanatics.com/civ3/reference/
@ Spoonwood -- thanks for the clarification.