I've seen a few posts regarding people wanting a remote release for a camera. I found it quite easy to do directly with my A610. I soldered a socket to the shutter switch terminals in my A610 so that the camera can take a standard shutter release cable designed for the EOS 450D (which I had already).
If you're going to do this on an A610, the required soldering points are fairly easy to access, though difficult to solder to if you don't have access to a really fine-tipped iron. But if you know what you're doing it shouldn't take more than an hour. I can't vouch for other camera models though. In my case there was a little bit of modification of the casing required to allow the wires to leave the case & enter the socket. And some thought needed to go into routing the wires to ensure that the case would close properly without putting stress on parts. With the camera turned off, a multimeter measuring resistance could tell me which terminals were shorted out by half & full presses of the shutter button so that told me which order to solder the wires to the socket.
Next project is an external mic socket & provision for a 5th battery (ensuring longer service per charge out of one set) for both my A610 & S2IS, & also a remote shutter release for the S2IS.
Photo attachments:
1- Soldering extra wires onto the tiny terminal of a surface-mounted switch can be tricky!
2- How the wires can be routed.
-Shawn
