Its simple, really. How much distance do you need? Do you need a timer? Do you need wireless?

If you can work within a cabled range, you can do that anywhere from 3 to 12 feet or so, then get a simple remote tether, I got a few on Ebay from a chinese manufacturer, cheap crap, works great.

example: http://cgi.ebay.com/Remote-Switch-S6...item3f0939e154

If you need timer functions, for use with timed bulb exposures and precise round the clock timer controls, than you need an intervaluometer remote, which are very similar, with different timer options, usually ~$50, cheap ebay stuff.

Ex: http://cgi.ebay.com/Timer-Remote-TR-...item3cb72c9c39

Normally I'm not a cheap stuff kind of guy, but this stuff is so simple, no need to pay the middle man mark-up for the same end product..

IF on the other hand you need a wireless option, then its similar to the above two, but a wireless receiver in the middle

Example: http://cgi.ebay.com/Cleon-II-Wireles...item3cb72c9c11

Not endorsing those exact ones, just linking to the first quick one, make sure the cable is long enough for your needs and make sure to pick the right one for your intended use. The camera already has a built in 2 second and 10 second self-timer in it, which will work with the simple straight cable remote, you don't need the intervaluometer for 10 second timer. The simple one will also have a switch on it which will allow it to do bulb exposures.

Granted the intervaluometer is a lot of fancy bells and whistles, but i figured at ~ $50 its worth mentioning.