You may want to try https://bitcoinnotify.com

It does not require installing anything on your server.

Accepting Bitcoins is as simple as handling HTTP request (the payment notification).

What's important, Bitcoins go directly to your wallet, which you can keep safely offline. This is in contrast to other solutions like MyBitcoin, BitWillet or BitPay.

BitcoinNotify never receives, stores, or sends any coins - and it is still able to notify you about payments to your Bitcoin addresses.

SMS, e-mail and Jabber notifications are also supported.