As far as I know there is no way at the moment. Some people may be fine with seeing the unconfirmed payment just going through, but most will want at least 1 confirmation. Some people have suggested that this could be mitigated in the future by using 'trusted' addresses or payment gateways.

Edit: Litecoinguy is correct. With small transactions there's not really much risk involved.

I don't believe this is correct. By definition you cannot see an unconfirmed transaction in the blockchain. What makes unconfirmed transactions generally safe (but see below) is that once a tx  has propagated across the network, any double spend of the same coins will be rejected. Since it only takes a few seconds for a tx to propagate, for all practical purposes bitcoin transactions are instant and except for extremely high value transactions (where special but expensive attacks might be mounted), there is no need to wait for confirmation.

But nb it is my understanding that although it is generally safe to accept unconfirmed payments, it is NOT safe to accept unconfirmed payments that include any unconfirmed inputs (because of tx malleability). However, this is a special case which is being addressed in the latest release of QT and does not affect the broad picture that unconfirmed transactions are generally safe as long as the tx inputs are themselves all confirmed.

Every in person transaction that I have done in a retail settings has been accepted with zero confirms. Brick and Mortar businesses that accept bitcoin are very trusting of bitcoiners in general, and most are small ticket items (food, coffee, etc), where zero confirms are adequate.