Some questions, if I may.
An XBEE module will be connected to the arduino as well as an ethernet shield.
Which XBee module? Which ethernet shield?
the arduino needs to be monitoring the serial port in realtime and sending all data it receives from the XBEE to a specified server on the internet via the arduino Ethernet library
What is sending the data? How much? How fast?
the arduino may need to buffer incoming data so that nothing is lost.. need more insight into this..
The Arduino doesn't have a lot of space for a buffer. If the data comes in faster than it goes out, any buffer will eventually fill up. So, the amount of incoming data is critical. How many bits/bytes/whatever per second/minute/hour/day/whatever?
I’m looking for a developer that can write the arduino code required to make this happen .. it’s a pretty simple application, I just need it to be optimized to handle the possibility of receiving data from many XBEE sensors at the same time and not dropping any resulting data in the process..
Ah, a new requirement snuck in at the very end. The new one makes the job much more complicated. It may not really be that simple.
Where are you located? How will the testing be performed? Need date? Compensation?