PSE Pioneer Southwest Energy Partners L.P. Pioneer Southwest Energy Partners Lp

Pioneer Southwest Energy Partners L.P. (�Pioneer Southwest�) (NYSE:PSE) today announced that Rich Dealy, Executive Vice President and CFO, will present at the Wachovia MLP Conference on December 9, 2008 at 11:35 a.m. ET. Any interested person may listen to the live presentation and view the presentation slides during the conference, or hear an archived version afterwards, by logging on to Pioneer Southwest Energy's website www.pioneersouthwest.com, selecting �Investors,� and then selecting �Investor Presentations.� Pioneer Southwest is a Delaware limited partnership formed by Pioneer Natural Resources Company to own and acquire oil and gas assets in its area of operations. This area includes onshore Texas and eight counties in the southeast region of New Mexico.