The undoubted market leader when it comes to Tennis trading is the service offered by Trade shark . (Its so good in fact that the methods used have been imitated recently and passed off as another service!).
For a one off fee of £39 you get access to some training videos and a detailed guide on how to use the various strategies detailed – the membership fee also gives you access to the forum where you can pick up some really usefull advice. The guy who runs the service is also very helpful and generally will return relative emails quite quickly.
Heres an example of the type of in depth information that is posted up on the site when tournaments take place:
A new addition to the world of tennis trading services is TOTAL TENNIS TRADING. Very in depth with lots of videos that demonstrate various ideas quite nicely if thats your prefrerred method of learning. The only downside is the over the top advertsing page but if you ignore that its actually good stuff. The service costs $79
Lastly my personal favourite is the Tennis service offered over at the BETFAIR GURU . Rather than just paying out for an instruction course and being left to your own devices the guru actually guides you through the trades in the chat room. Invalubale if you prefer a low risk approach. More details of the Guru service are listed here.