What you're looking for is something called an Intervalometer.
These can be programmed to automatically take shots at certain intervals.
They used to be specialist accessories, but these days the facility is offered in some PC remote control software packages and are even built-into some higher-end cameras.
For example, the Canon 40D and 450D / XSi come with remote control software as standard and the Nikon D300 has the facility built into the camera.
The third-party program DSLR Remote Pro
also offers PC remote control of most canon DSLRs.
I'm not sure about the E-510, but I know the optional Olympus Studio 2 software can remote contreol the E-3.
Failing that, there's still the option to press the button yourself for every shot! I had to do that every minute 100 times for the timelapse in our Nikon D60 video!