There is no Word Pro app for the iPad. There are several other MS Office compatible apps for the iPad. They each have their strengths and weaknesses. None of them are 100% compatible.
Here are some member reviews of the more popular choices.
There are also a couple of new virtual desktop services that you may want to check out. They need a fast broadband connection and still in their startup phase: CloudOn and OnLive.
I see Twerppoet has already given you some excellent links.
The IPad Forum is a community of members from all walks of life and from all over the world coming together to share our experiences and to help each other learn about this wonderful piece of technology the Ipad. There is a wealth of information already here in the many threads we have so doing some searches will answer most of the questions you have. If then you cannot find the answer you are seeking then by all means post your question. There are many friendly and informed members here only too willing to help you.