How do I accept bitcoin payments at a real world store? From what I understand, there are some requirements for using bitcoins at a physical store:


Both the store owner and the client must have Internet access
The client must have a cellphone or a laptop to issue the payment
The seller must have a way to confirm that the coins were sent.


The biggest problem is the confirmation. Since it is risky to accept transactions with 0 confirmations, it will take around 10 minutes before a single confirmation occurs and allows the real world transaction to be completed.  The more confirmations that occur, the less risky it is.

That said, what is the best way for a store owner to securely accept bitcoins?
Green address technique from Instawallet. System sends bitcoins from well known address called Green Address and if recipient trusts Instawallet or any other major organization that uses same technique, then he or she can accept payment without waiting for confirmations. This is what already implemented but it solves only the third problem.

Instant TX for established business relationships is in early development stage but it can solve all three of the problems, with an exception that only retailer needs to have internet access. For example, transaction could be printed by customer on a piece of paper, handed over and accepted instantly by retailer, and it still would be secure. The idea is very promising because such transaction could be sent over internet or by any other way directly from buyer to seller and won't use any of Bitcoin Network resources, and it would be economically fisible to make automatic payments for a service that costs several micro bitcoins.