HTC is one of the major OEMs of Windows Mobile devices. They produced devices ranging from the HTC Universal, HTC VOX, 6700, Treo 700 series, HTC P3550, HTC Advantage, S620, P4350, P3300, MeteoR, TyTn? etc.

Recently they have decided to sell their hardware under the HTC brand through retailers such as Mobile Planet.

Links

HTC Homepage
HTC Wiki Product info