I'm a software developer working on just such a program. Right now it's just in the development stages.
We currently have a software package that can convert any PC from 8088 up to P-III into a P-IV. It went on sale last April 1st.
The program that will hopefully make me a lot of money is currently in Beta test. It can turn a 1983 Ford Tempo into a 2001 Porsche 911 Turbo. Just plug your laptop into the car's onboard computer diagnostic port, and execute the software. Right now it's a little buggy, some Beta testers are reporting that their cars were mistakenly converted to 1997 Dodge Caravans for some reason. You can bet we'll have the bugs ironed out before our software package hits the shelves.
We've also been getting a lot of requests for a software package to convert existing girlfriends into various famouse people (i.e. Jennifer Love Hewitt, Sarah Michelle Gellar, Britney Spears, Christina Aguilera, etc). We will probably start development on this software package in Q4 2001.