Q: Where can I get a driver for my VIA chipset to support a widescreen monitor/resolution?
A: The availability of a driver to support widescreen depends on what the chipset supports and whether or not the manufacturer of the motherboard featuring the VIA integrated chipset has requested the driver. All P4 and K8 chipsets do not support widescreen. This includes the following chipsets: PM880, PT800, PM800, P4X533, P4X400, P4X333, P4X266A, P4X266E, P4X266, P4M266 K8T900, K8T890, K8M890, K8T800 Pro, K8T800, K8M800. Older legacy chipsets supporting CPUs such as the Intel Pentium III and AMD Athlon and Duron processors, also do not support widescreen. The CN700, CX700 and CN896 chipsets are capable of supporting widescreen. To support widescreen the system BIOS must support it as well as the driver. You should obtain your latest BIOS and driver from the motherboard manufacturer and if widescreen is not supported, ask the manufacturer to update the BIOS and driver to support widescreen. The VX800, VX855 and later chipsets support widescreen as a standard rule, so all drivers for those chips on this website and on the motherboard manufacturer's websites will include this support.
VIA and S3 did NOT release any upgraded video bios with widescreen support. So the only option you have is adding a video card that does support widescreen, sorry.