I find the only way to become something is to do it. This does raise the usual 'catch-22' jollity of not being able to do the thing because you're not a thing-doer already, but that's life.
so, if you want the lovely, important-sounding job title then you'll have to find a way to get to do some architecture in your current role. Try a white paper type of email explaining (constructively) how your group could improve an aspect of the current system. If people like it, and can implement it, then you'll be a step closer to being an architect. Next step after that would be to mention career progression at your review and push for a more formal promotion to that type of role.
You will haver to get more knowledge than just .net development though. Architects have to know systems in general, system designs (not those little development patterns), you have to explain how to produce scalable, reliable, fault-tolerant, maintainable, supportable systems. Much of that work doesn't really involve development (ie an architecture like that could be implemented in .net, or java, or c++ or ruby on rails, the coding aspects is of much less importance).
Of course, I might be describing a systems architect role there, or a solution architect. Which just goes to show how useless these pigeon-hole names are. You could do what myself and possibly Mr Butterworth thinks - just do your job the best you can and not worry about what kind of job-title-buzzwords you have on your business cards.