Sorry Ben was on the phone
Internal sales or inside sales, means selling from within the company. Meaning most of your sales are conducted via the phone or the web, it is usually a sales support team to help the outbound sales team i.e the Sales Manager, BDM's and Accounts Managers.
It does consist of a lot of cold calling and prospecting from within the company. The job is usually done by very experienced sales people and is not usually an entry level job. Because internal sales consists of selling product (i.e something tangible) it and generally has no value added benefit, it can be used soley by companies who aren't prepared to pay what outbound sales staff demand.