How do I upgrade my units in Civ 4?

[Sovereign]

I saw the AI just upgrade their propeller fighters and bombers to Jet Fighters and Stealth Bombers. It must have an upgrade option as it had 2 of each in one city and upgraded them all in 1 turn). How can I upgrade my units like that? In Civ 3, I recall there was a command to upgrade, say, a musketman to a rifleman, or a Tank to a Modern Armor- I think it was SHIFT+U or ALT+U something.

If I could upgrade my stuff like the AI does, then I should be all set. Its just that I can't seem to find how or where to upgrade my units in the manual or in the Civ 4 screen. If I can't upgrade, then this is a major cheat for the AI- being able to upgrade everything in a snap.

[Balderdash]

When you select a unit, if it is upgradeable, there will be an Upgrade icon down there in the action bar. Hold down the [Alt] key when clicking it to upgrade all the same units on the map. (Also, holding down the [Alt] key and just moving the mouse over the icon will tell you how much it will cost to upgrade all the units. It can be pretty expensive sometimes.)

And not that you asked specifically, but as far as what will upgrade into what, I don't know. I wish there were a nice table in the manual for just this info, but there's not. Has anyone compiled such a list yet?

[shawnj]

If you open the Civilopedia (F12) and look in the units
section it shows what units upgrade to. Also you do
not need to have the units you want to upgrade inside a city.

[guermantes]

.... however, you do need to have the units inside your cultural borders to be presented with the upgrading option...

[Dis]

Originally posted by guermantes
.... however, you do need to have the units inside your cultural borders to be presented with the upgrading option...

ahh, cool info. I was wondering why sometimes I could upgrade ships out at sea, and sometimes I couldn't.

Realistically ships should be in port to upgrade. And units in barracks. But this is an example when gameplay takes precedence over realism. As Civ3 was a pain in the ass juggling all your units to upgrade to cities with barracks in them. And ships to cities with harbours.