glad you found the easy fix of adjusting cable tension. Folks having chronic problems switching from the smaller chainring up to the larger chainring in the front may also want to look into seeing if their larger chainrings have pins and ramps.

Pins are little steel bumps on the back of your chainring (facing the smaller ring) which give a little boost to the chain. Shimano makes them, so you can change out the chainring to one with pins. It totally solved my problem of the chain not switching up, even when the derailleur and cable were adjusted.

Ramps i think are little divots in the back of the chainring itself which help facilitate lifting the chain up.

You can read more about it (and see a picture!) at http://www.sheldonbrown.com/gloss_ra-e.html