Company’s First IT Budget

I am trying to develop our company’s first true IT budget. In the past, IT was simply lumped into a general “corporate administration” figure, that didn’t capture any details, nor was it ever adequate at attempting to address true IT expenditures.
With a new strategic direction, which includes a heavy technology focus (including software development, state-of-the-art ACD/IVR, etc.), this must change.

I have been part of budgeting processes in other companies, but there was always something to work from. I don’t have that benefit here.

Can someone point me to some sample budgets, books, etc. that can help me on the way?