What kind of application you are trying to automate? If it is a browser (esp. IE and FireFox) you can automate it with VBscript quite easily... Here is a great example of what can be done... First google result for "automate ie vbscript"
I took a quick look at the AUTOnomyV Website and it's an interesting looking tool. If you decide to go with it, please post back what your experience with it is like.
I would second the question asked, why specifically VBScript? There are a number of open source tools available for Web testing. Personally, I like WatiN, which lets me code in C#, but since your application is in Java/Ruby on Rails, you may want to consider Watir (which WatiN was based upon). By all accounts that I've heard, Watir is an excellent tool and Ruby a powerful language that is not too difficult to learn.
I'm also sure that there are a number of other tools that people can give recommendations for, if you are open to other languages.