I don't have a cell phone, but Google App Engine needs an SMS message to verify the account. Is there another way to complete the registration?
I'm surprised they don't use a Gmail account to do this.
Edit : Google created one for me, problem solved.
No. If you don't have a way to receive SMS, you can fill out the SMS issues form to have an account created for you.
Actually Google have instigated quite strong protection on new gmail accounts, at least here in the UK @googlemail.co.uk addresses require SMS confirmation as well.
They probably don't use Gmail because there are too many Gmail accounts in the wild. Gmail now requires verification by SMS or a voice call, but it didn't always. App Engine is limited to SMS only (no automated voice call option).
You probably have a friend whose cell phone you can use.
You could sign up with any web based sms service that enables you to receive sms via virtual phone numbers.
The first one i found that offers a free trial was esendex.co.uk.
But quick search will get you many more.
Or you could just ask somebody to lend you his phone for 5min in ... receiving sms is free after all.