Have done this tons of times with my now 3YO on US. My advice--purchase 1 of these: http://www.toysrus.com/product/index...uctId=12074529

On your day of travel:
1)Check in at the kiosk. Select however many bags you wish to check, excluding the car seat. When the agent calls your name/destination, tell them that you need to check a car seat. It will be FREE, even if you have to pay for the other bag(s) as long as you DON'T select it on the kiosk.

2) Take your baby in their stroller to the gate. Its much easier wheeling them around this way. At the gate, grab a gate check ticket. At the bottom of the ramp, put the stroller into one of these: http://www.toysrus.com/product/index...ductId=2967918
It will provide protection from dirt and make your stroller recognizable.

3) Relax. The hard part is now over provided you've brought extra everything for your child in case of emergency on board.

4)Be sure to collect your stroller when you arrive (either on the jet bridge or plane side)

Enjoy your trip, let me know if you need any further assistance.