[bojan]

For focusing: http://www.xmission.com/~jstanley/focusassist/
It can also be used for exposures.. up to 30 sec (at least this is what is possible for 400D)
For exposure and everything else: Iris http://www.astrosurf.com/buil/us/iris/iris.htm
or:
http://www.stark-labs.com/DSLR_Shutter.html
http://astrotips.com/Downloads-index...LR_Timer.phtml
http://www.brothersoft.com/cy-dslr-timer-181418.html
http://home.arcor.de/th.bach/Software/Software2En.htm

You will need cable for this.. easy to build, see above websites for schematic. Also here:
http://www.dslrfocus.com/help/eoscable.htm