Scott Hanselman has an interesting discussion on the ever elusive mirage of accurate software esitmation here.
It also points to a number of software estimation techniques like Wideband Delphi, Proxy etc along with softwares that can help you with the estimation, like Planix, planningpoker, Steve McConnel’s Construx Estimate and SpreadsheetGear.
The post is very accurately titled as Software Estimation: Remember that Targets are not Estimates.
I liked the quote from Steve McConnel’s Book, Software Estimation: Demystifying the Black Art:
Considering that optimism is a near-universal fact of human nature, software estimates are often undermined by what I think of as a Collusion of Optimists. Developers present estimates that are optimistic. Executives like the optimistic estimates because they imply that desirable business targets are achievable. Managers like the estimates because they imply that they can support upper management’s objectives. And so the software project is off and running with no one ever taking a critical look at whether the estimates were well founded in the first place.
This post is a nice reminder that, Targets are not estimates.