Hey Gary
First off you need a budget. Once you have decided upon a budget you can then start to look at machines within that bracket.
TMC is a wealth of information on Roasting. This includes things like a Whirley Pop, Pop Corn opper, I Roast, Gene and Hottops.
Once you have decided on a budget, you can then look at how often you will roast and how much you will roast. Your volume will effect what machine you wish to use.
I started using a Whirley Pop and I know that this was for me suiperior to the Gene for sheer quality of roast/profiling (How you roast the beans). It took some practise, however once I had got it cracked I acheived some of my best roasts ever. I wrote an article on this and it is on:
www.coffeeinfo.co.uk
Under articles I think...
Sweet Marias is also a great site to explore the different methods with the pros and cons given equal voice. You will find advocates for each method and usually several views with two people!!! So to re-cap:
1. Budget
2. Quantity
3. How often will you roast
4. Do you mind a hands on approach
5. Are you willing to experiment
Above all (And I say this often), don't get too anal about it. It is a really enjoyable hobby and if you can staick at it and are willing to learn from mistakes, it will reap huge self satisfaction. There is also a short WIKI entry here about Home Roasting.
Hope that is of some use Gary.
Thankx
Matt