Ground and balloon-based:

• ATCA
• BAM
• BOOMERanG
• CAT
• CBI
• DASI
• DIMES
• FIRS
• Jodrell Bank
• MAX/MAXIMA, more.
• MSAM
• OVRO
• POLAR
• Polatron
• Python
• South Pole
• SuZIE
• Tenerife
• TopHat
• Viper, more.
• VSA
• White Dish, more.

Satellite:

• MAP
• Planck (COBRAS/SAMBA)

Theory:

• Max Tegmarks' CMB site at the University of Pennsylvania.
• George Smoot's Astrophysics Research Program at LBL.
• Wayne Hu's Tour of CMB at the University of Chicago.
• Douglas Scott's CMB Page at the University of British Columbia.

Software:

• CMBFAST
• COMBAT
• COSMICS, more.
• HEALPix
• IGLOO
• MADCAP
• WOMBAT

Miscellaneous:

• Penn physics department
• CMB Experiments at Princeton.
• The old version of this site.