Is there a way to initiate a payment request in bitcoin? I'm writing a recurring billing system and I want to be able to contact a customer and request a certain amount of money. Is this possible via bitcoin?

If not, could a URL be provided the customer so he can simply click it and it opens the bitcoin app and initiates a payment process?
You can now use the Bitcoin payment protocol to do this.

Here is an easy to use implementation from Bitpay.

There are already a few wallets that support this (including the reference client).  More will be released soon.

See:


BIP 70
BIP 71
BIP 72
BIP 73