Used to be that you could get a minimum of 500 Delta SkyMiles for stays at posh SRS-WORLDHOTELS properties. But under a new partnership agreement between Delta and SRS, the duo is offering up to 4,500 additional bonus miles for stays.

SRS has a collection of 400 worldwide independent hotels and resorts. Most are hotels you probably have not heard of, like the Berlaya Eden Park Hotel in London. But, they do have familiar names such as the Copley Square Hotel in Boston, the Park Central in New York City, the St. James Club in London, the Melrose in Dallas and the Pan Pacific Hotels. In October, it announced a new marketing agreement with Delta. The additional 4,500 bonus miles promotion is good through April 30.

Here’s how it works: Stay one or two nights and earn an additional 500 miles. Stay three or four nights and get 1,000 miles. Five or more night stays bring in a hefty 4,500 miles. For a list of SRS hotels willing to up the ante for this great miles giveaway, call 800-223-5652 or go the SRS Web site at http://www.srs-worldhotels.com.