An attachment that may be coupled to a wireless communication device, such as a cellular telephone, personal digital assistant (PDA), or the like, to perform commercial or other information transactions, as well as to an apparatus or system for conducting such transactions. The wireless communication device generally includes an antenna that may be directly accessed by a processor in the attachment for transmission of data to a remote computer over a communication network. The attachment may also include an input device, such as a magnetic stripe reader, smartcard reader, barcode scanner, optical scanner, fingerprint scanner, proximity detector, or the like. When input is received at the input device, the input information may be sent to the attachment processor for processing and transmission to the remote computer via the antenna. The remote computer may process the received attachment-processed data and generate a response to send to the device processor.