There are three main types of artificial life caty… soft (from software), hard (from hardware or robots) and wet (like biochemistry).
With hardware, there tend to be robots that can perform their own tasks without any interaction from humans. Biochemistry tends to focus around creating synthetic (man made) DNA, whilst software is the attempt to create a machine that thinks on its own – a computer with a brain. 😀
People use different definitions of “artificial life” depending on what they’re trying to sell … I mean, “do” 😉
Just last month there was a big news story that Craig Venter, who is famous for running the first commercial project to read the human genome (the entire instruction book for building us, coded in the DNA), and his team had built the first “artificial life”. However, what was actually done was to take the code for a bacteria found in nature, then copy this code back into the DNA (using a machine and some bottles of chemicals), then stick this machine-made DNA back into a cell without a nucleus (so without its own DNA). In this way the team claims to have made artificial like. However, its really like “photocopying” another micro-organisms, in this case a bacteria called “Mycoplasma genitalium”. They used that one because it is very small, which made their job easier. From the second part of the name you might be able to work out what part of the body it infects …
Anyway, I don’t think that this is a truly artificial life form – just a very expensive way of making a copy. However, it is an important step towards making true artificial life. The next step would involve not copying existing DNA, but designing new DNA sequences to have new functions, putting them into a cell and making the cells function differently.