I *highly* recommend the Canon VB-Cxx series of cameras. They have built in web servers, so you don't need to have them hooked up to a computer. The best part is, you can pan, tilt, and zoooooom way in. I travel all the time (I'm in Hong Kong at the moment) and I use it to check on my tank. I can easily zoom right into a coral, to the point of checking out the individual polyps using a VB-C50ir. I loved the camera so much, I bought a couple of them as well as two of the even higher grade VB-C60, which I'm going to use for home security, my fish room, the other side of the tank, etc.
The software that comes with these is outstanding. You can have it, for example, create presets of a given pan, tilt, and zoom. You can then have it take pictures of the various presets (I think I have a dozen or so of them) automatically on a schedule that you designate. I have these automatically downloaded to a server (they come with the software to do so) and I'm eventually going to use all those pictures to do time lapse photography of my tank and some of my favorite corals. How cool is that!
It has other features which are really cool for home security. For example, you can designate a field of view so that if anything moves in that part of the camera's view, it will automatically start taking pictures and recording the event. You can even tell the camera to follow whatever it is that is moving (ie your daughter's boyfriend who is sneaking into your house
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. All the setup is drop down menus, etc. so it's really easy. The key is that you need an ethernet connection and power by the camera. Other than that, it's easy as pie.
While the quality and ease of use is awesome, the price is a bit scary. New, the VB-C50ir runs about $1,200 and the VB-C60 is around $1,400. If you don't mind waiting a few weeks for a great deal, you can do what I did: I've bought all of mine on ebay and I typically paid around $400-$500 each. Only one of the six I bought had a problem: a single bad pixel.
I hope that helps!