By default, works of authorship are owned by the author upon creation of the work. This often comes as a surprise to most business owners. Works of authorship include designs, written materials, websites, and even source code! To protect yourself, make sure your independent contractors have agreed that you own the material you are paying them to produce.
A work for hire agreement executed BEFORE the work is created resolves this issue. The agreement should also protect you from infringement of your own intellectual property by the independent contractor while he is working on your behalf. If a work for hire agreement is not executed, an assignment agreement is needed for your company to own any right to the work of authorship. Your IP lawyer can assist you in preparing a work for hire agreement tailored to your specific needs.