Here are links to the most widely used PPO networks in Colorado.  You can check to see if your physicians are listed.  It is still recommended though, that you call your physician's office directly to confirm that listings are up to date.

http://www.humana.com   Humana Home Page - Find a Provider in Left Frame

http://www.mygreatwest.com  Great West Network

http://www.phcs.com   Private Health Care Systems

http://www.sloanslake.com   Sloan's Lake Network

http://www.provider.uhc.com   United Health Care Network

http://provider-directory.anthem.com/awp/landing.asp  Anthem Blue Cross Network

http://www.covercolorado.org   Cover Colorado - State Funded Safety Net for Otherwise Uninsurable

HSA Colorado Home Page, What is an HSA?, Health Savings Account Example,  HSA Qualified Espenses, HSA Media Presentation, HSA Qualified Personal Quote, Instant HSA Quotes, HSA Online Applications, Colorado PPO Networks, Health Savings Account Library, Related Links Page, HSA FAQ, Medical Information, Maternity Options