Napping Too Long
So you've got a schedule and you stick to it, but your baby's napping too long? If your child has to be awakened from long naps, and if she is routinely cranky, irritable, aggressive, overly active, or overly emotional, she is probably sleep-deprived. Different people require different amounts of sleep in a 24-hour period. Establish a bedtime at night that ensures enough sleep for your child, factoring in a reasonable amount of sleep during the day. This might be earlier than her peers' bedtimes, but don't let that be a concern; some children go sleep before 7 PM every night. If that doesn't work, consult your pediatrician; your child might have a medical condition (such as enlarged tonsils) that is preventing her from getting enough restful sleep.
Crankiness Upon Waking
Your child's not sleep-deprived, you say, simply unpleasant? Well, just as people need different amounts of time to sleep, they need different amounts of time to transition to and from sleep. You can help your child learn to shake the grumpies by establishing a naptime routine in reverse: move gradually from relaxation to activity. Turn up the lights a little at a time, speak quietly, change his diaper, cuddle for bit, and read a few books. Move from soothing books to funny books and add in a little tickling when he's ready. Some people need to eat right away upon waking due to low blood sugar, so that's a solution well worth testing, too. With a little help, your child will feel like himself again soon, keeping you busy 'til bedtime.
For more support in establishing healthy sleep patterns, check out these resources: The Happiest Baby on the Block: The New Way to Calm Crying and Help Your Baby Sleep Longer by Harvey Karp; The No-Cry Solution: Gentle Ways to Help Your Baby Sleep Through the Night by Elizabeth Pantley; and the classic (and somewhat hardcore) Solve Your Child's Sleep Problems by Richard Ferber.