In biking you'll be holding a fixed position for a long time, and the best way to develop that kind of strength is by doing what is known as isometric strength exercises. Here's a good example: Clasp your hands together and press them against each other as hard as you can. Nothing will move, but you'll be exerting maximum force. You're building strength in a fixed position (without movement) by pressing against an immovable force (your other hand). Another example is pushing with all your might against a wall.

A good example of an isometric exercise useful for biking is a wall squat (holding a squat position against a wall for as long as you can). Another is getting in position to do a floor push-up, but holding the start position (before you descend) for as long as you can. Or descending halfway and then holding that position for as long as you can. If you're still with me, try this one: Get in the position a swimmer would take as he was poised to dive (bent at the waist, butt out, knees bent); now hold that position. Make sure you get down low. (Hint: for all of the above, start with a count of 10; if you can work up to 60 to 90 seconds, you're in amazing shape!)

Don't neglect basic core exercises that will strengthen the abs (crunches and the like) and lower back. To strengthen the much-needed hip flexors, Terry Kerrigan likes this one: Jump up and touch your knees. Repeat for 10 reps. If you've got access to a gym with the old Cybex hip-flexor machine, use it. Or attach a cable to one foot, face away from the cable, bring your knee up (pulling the cable with you) and then extend the leg backwards. Do ten reps on each leg and then switch