IPad – Pair magic keyboard with iPad

I don't think this is your problem, but it might be and doesn't seem to have been raised elsewhere. I bought a new MacBook Pro running Lion a few months ago, and found that the (also new) Magic Mouse would not connect automatically—I had to force it to connect after any disconnection from switching off the MM or from rebooting the MacBook.

One of the genii at the Genius Bar, after ½ hour of experimenting and in the process of telling me that Lion would have to be reloaded, suddenly realized that the MM connected upon being clicked. He stated that he had not run into this before and that it must be a new feature in Lion related to battery preservation.

Bottom line, try a single mouse click to initiate the Bluetooth connection.

No, it can only be paired to one computer at at time according to Magic Trackpad Manual. You would need to un pair and then re pair it to another computer in order to use it on both computers.

Here's the extract from the manual:

After you pair your Apple Magic Trackpad with a Mac, you can pair it again with a different Mac. To do this, you first remove the existing pairing and then pair the trackpad again.