Now that you've written your song/s, the next step would be to make a recording so that others can hear it. If you have written enough songs to make an album, and have the resources to do so, go ahead and have your album produced by a professional producer who has the experience and all the gear needed to make your album sound professional. No home recording can ever beat that! Before you do that though, I would advice you to read Pastor Wah Lok's article on "Recording and Marketing an Album".
If you are planning to record the song yourself, there are many options as to how you can go about doing it. It really boils down to the equipment you have access to. There are many sites online that teaches you how to build your own homestudio.
These are a few free recording software available online.
And of course, for Apple users, there's always GarageBand.