Most companies will want to block their entire companies IP range so that the data in Google Analytics is not skewed by developers, testers, managers etc. However there are situations where you still want to collect data from a couple of computers. For example if your taking phone orders and you want the revenue to be recorded in Google Analytics then you obviously want that CSR's orders to be reflected. So you would want to allow her computer's data. We all have our own reasons to use this solution – so enough chit chat lets get to the work around.
It's a two step process: Find all the details here: http://www.epikone.com/blog/2006/07/11/count-me-out/
This work around is not perfect, but it will work in small offices, or in situations where you only want to block one computer.