Be careful.

My 12/10 MCI bill lists (on the back, in fine print) a rate increase, effective 1/1/02, from 5 cents a minute to 30 cents a minute off-peak, and from 10 cents a minute to 35 cents a minute peak (except for a 10 cents rate Sundays). Yowsers!

Needless to say, I'm switching away. You might want to check your most recent bill so you don't fall into this trap.