wireless serial data?

I have a couple of retail stores that have multiple wireless sensors that send simple serial data to a receiver that allows connection to a PC. I have been asked to create a simple web server for each receiver and a simple web interface to present the data. The web server etc.. is no problem but handling the registering and comparision of the sensors is the difficult part. I do not know the mac or serial number of each sensor and I will not be installing the servers at the sites. I need the ability to receive the data parse the data which contains the serial number and payload.

What is the best way to handle the writing to the PIC's EEprom and the comparing of all incoming packets to whats already registered? On top of that I will have some basic calculations on the payload. The web page will be a basic interface with the serial number, the number as they have registered (1-X), raw packet, calculated data and thats about it.

I have never done anything like this and need some guidance a point in the direction to were I can find information to assist me in this project. Maybe a code snippet.

Any help would be greatly appreciated,

Scott