tangentspace view vector?

That depends on what you have already. If, for example, you have the view vector in world space, you just multiply it by a matrix that tranforms from world space to tangent space. If you have it in view space, you'd have to use a matrix that transforms from view space to tangent space, or you'd have to first bring the view space vector into world space and then use the first matrix.

This page has a discussion of the derivation of the tangent space matrix.

Actually it's spelled voila... it's french. Not to be confused with viola, which is like a large violin. Neither are to be confused with the topic which I seem to be off.