I am an experienced programmer but new to VB. I am starting a new project and I'd appreciate pointers to get me started.

I want to develop a 'content analysis'add-in for Microsoft Word. Similar in many ways to the spellchecker, it will scan all the words in the current document and highlight the ones that match a pre-defined list. When the user clicks on (or hovers over or whatever) the highlighted word, the user will be presented with a blurb about the proper use of the highlighted word and/or a clickable list of suggested alternatives for that word.

From the research I have aleady done on how to get started on this project I have the following questions:

(1) Could this be done using just the VBA tools that come with Microsoft Office?

(2) If a more robust programming tool is needed, must it be Microsoft Visual Studio, or are there better/cheaper alternatives?

(3) Would I need to develop a separate version of the program for each version of Word (e.g., Word 2003/XP/2000/98) that it might be run on?

Thanks in advance for any pointers to get me started, links to tutorials on the web, keywords that I can use to search this site's forums or google generally, or, especially, working code samples.