Being a total noob on the subject I jsut wanted clarification, does power training totally forego the need for an HRM?

I was reading a guide on how to use this upcoming product, the ibike pro - http://www.ibikesports.com/documents...ining_book.pdf and you seem to get your baseline measurements based on doing several test drills.

So similar to HR, is your power at LT pretty much constant over differnet conditions (like climbing versus flats). The way I understand my HR/LT is that once I go beyond that poing then I'm building up lactic acid. Is there a Power/LT equivalent?

info on this would be greatly appreciated.