The emergence and acceptance of Sales 2.0 approaches has helped (forced?) Marketing and Sales to work together. Their alignment is critical to building and sustaining a qualified sales pipeline. In our practice we see Sales and Marketing coming together in areas such as the definition of a "sales ready" lead and an overall lead rating system. This is a great start but to optimize we recommend you go further.
Today, the sales/lead pipeline must flow in both directions. Marketing generates the leads but if they are not ready for conversion, sales needs to communicate back to marketing. Then marketing can continue to nurture the lead until it becomes sales ready.
By implementing a two-way feedback and measurement system, you will achieve higher conversion rates and lower your cost per lead.