Well there is a handy resource that allows you to spy on them and see all this information and more. Keyword Spy is a very easy to use tool and you can get a lot of vlaue out of it by just using the free trial version.

I started to use it recently and it does become quite addictive to see what people are bidding on and typically how much it can cost per click in different industries for different keywords.

The paid version of the service gives you even more detail and lots of very valuable information. If you are using pay per click marketing in your marketing arsenal then you should definately give Keywordspy a try