You can sell computer software to anyone, especially to business owners. The irony is that because the target market is so huge, as a merchant you will have to make sure that you are selling a product that works and will give you a good reputation online, resulting in repeat sales/downloads. If you're the software provider, then you must provide trial versions (beta), and upgrades.

The good news is that software sells anytime of the year. However you can take advantage of certain occasions to sell software that are likely to rake in some profit such as Christmas PC games, holiday-themed digital clocks, etc.

Since you are dealing with digital files the medium is the Internet. You can sell in your own store or be hosted by a storefront provider. You can also advertise your products at online marketplaces and forums. If you intend to sell to a bigger international market, then you should be able to equip your store with features such as a shopping cart that accepts multiple currency or allows international shipping. You can also apply for an international merchant account.

The option to be hosted by an international merchant account provider is not for everyone. People from various parts of the world are likely to download a good software if they see one -- such as Skype or office tools. But can you process international currencies and credit cards? Does your shopping cart handle various languages? An international merchant account has a lot of advantages (less tax, less government interference, etc.) because the providers are located overseas. This is a good option if you intend to market your product offshore.