Tracking Conversions from Different Sources?

Hi All,

Can anybody give me a bit of advice and how to track conversion from different online sources.

I am promoting 5 different operators on my betting portal. So I know where customers are converting from on my site I have approx 5 sub codes per operator - in blogs, in odds comparison, in casinogames, in FAQ's, logged in and not logged in, etc.

What I want to track is the sources of customers coming to the site and how they convert. If I have 10 different sources - different link directories, links from other sites, natural search, PPC, etc - how do I track which sources are working well for me - not just traffic to my site but actual conversions (registration and deposit) to my different operators.

I know I can create more subcodes but that would soon become unmanageable - if I create a subcode per source for every different area on my site I would soon have 50 subcodes for just 10 sources (5 x 10) - and the number of sources is likely to increase dramatically.

How do you guys track the conversions from your different sources? So you know what source is sending the best converting traffic, and not just the most traffic.

I am using Google Analytics on my site which indicates the source. Can I track exits to my promoted operators from the different sources? That doesn't tell me who is converting just who is clicking through to my operators but it's a start.

I'm sure a lot of seasoned affiliates have been ingenious in over-coming this problem. Any pointers?

Thanks for your help

Chris.