Beginner Fish Questions

Hello All,

I'm trying to decide whether or not to get a small aquarium. One of my cats just loves to watch Animal Planet, and I thought about maybe getting a few fish. The only problem is that I know absolutely nothing about fish or how to care for them. I know that this is not simply a cat toy, but living things with needs. I'm still in the considering stage, so any information is greatly appreciated, such as:

What type of fish is easiest for a beginner?
What types of fish get along well together?
How many is a good starting number?
Fish tank, and water cleanup and care....The list just goes on.

Can anyone make some suggestions, and if you think its not a good idea to get an aquarium, please, feel free to say so. I'd rather know now, than have to mourn the loss of my newly aquired fish pets.

Jennifer