How to get rid of spam comments

Hi,

I don’t really understand it but I am getting lots of spam comments on my blog (and unfortunately at this stage a complete lack of genuine ones – but hey ho).

It’s not that it is a big deal to just mark them as spam but the thing that gets me is when I look at the time the comments were sent it never corresponds with any real traffic I can see when I look at my stat counter account? How can this be? And more importantly how can I stop it?

I am probably getting about 5 spam comments a day – it might not sound like a lot but it is annoying. Or does this just happen to everyone?