Komet,
I agree with Mike on this one. There are literally tons of keyless or remote entry systems on the market. Check with a local stereo place and they should have some recommendations. There are also a few good recommendations on some of the car audio sites on the internet where the installers post their opinions on the different systems.
I have also heard of alarm systems and remote entry systems in one package, which turn off the alarm and unlock the doors at the same time, which is really cool.
One other suggestion is to check the street rod sites, as these guys almost always pull the handles off the cars and need to use remote entry systems to get into them.
Best of luck,
Doug