Use Audacity, it's a freeware audio recorder and editor and used by lots of people. Getting rid of unwanted noise in your recordings is also really easy with this.
Here's how it's done: record your voice with some silence before or after your vocal, this silence contains 'your' noise. Select this silence (the more, the better), go to 'Effect > Noise Removal' and click on 'Get Noise Profile'. Audacity now knows what 'your' noise is and is able to remove it. You can do this by selecting the part that contains unwanted noise (which is basicallly everything), again go to 'Effect > Noise Removal' and click OK (you probably don't even need to mess with the sliders). Done correctly you should have a clean vocal now.