A freelancer provides something against a scope of work, usually using his or her resources (e.g. premises, tools etc.) to achieve the task.
An interim usually sits in the customers premises, sells his/her time (e.g. so much a day) and works to a looser brief (e.g. transform the IT system or deliver a web project) or he/she might cover for someone who is away. (e.g. on maternity leave) or when the task is not permanent.
A contractor would be a person who provides his/her time and expertise but is directed/supervised.
None of these are directly employed by the customer, but contracted.
What do you reckon?
B2Bgig can serve interims, contractors and freelancers and anyone looking for them.