The first think I think you want to do is make sure you're separating "Accounting" from "Finance". Having been in the latter field, it's easy to see the major differences between the two in terms of skills and abilities. It's the effective equivalent of calling a systems administrator a help desk tech.
With that being said, I would be hard pressed to see the value of an accountant in terms of IT. Typically your accounting roles are the ones that understand the "nitty gritty" of financial endeavors, such as taxes, depreciation schedules, and the like. Unless they are a user, there's probably very little in the IT world that accounting would have their hands in.
Finance, on the other hand, is probably involved in everything (or at least should be aware of it). Your Finance team typically looks more at the "big picture" in terms of forecasting, busines case analysis, opportunity costs, etc. They would be the ones running the different scenarios ("what if development takes three times as long...", "at what point do our benefits surpass our investment...", etc.) and ultimately would be the ones who would need to buy-off on any IT project.
Having been both in IT and in Finance, I can truly see the value that the latterorganization adds. They are an independent source, so they can recommend the tough decisions without a bias that IT-alone cannot provide. For instance, if a project goes well over-budget, it may make financial sense to cut our losses and abandon the project. Finance can't make that decision in a vacuum (they need to seek input from the appropriate sources), but they can provide an objective view, and get away from the "but we've already sunk $2M into this project, we don't want to waste that" philosophy (which has been used to justify FAR TOO MANY projects).