Here are some web links, biased towards my research interests (and the English speaking world):
A is for Atmosphere (past and present plots of meteorological data can be viewed at the ERA-40 Atlas, or at this NASA site), Antarctica (visit the British Antarctic Survey), and the AMS (and their Journal of the Atmospheric Sciences).
B is for Boulder (home of NCAR), and for Bristol (visit the Fluids Group in applied maths).
C is for Cambridge (DAMTP or the Newton Institute), Caltech (Planetary Sciences), Chicago (Geophysical Sciences), Colorado (PAOS or Applied Math at UC Boulder), Colorado State (Atmospheric Science), Columbia (Earth and Environmental Sciences), and the Courant Institute (Center for Atmosphere Ocean Science).
D is for Dynamics. Visit Dynamics of Atmospheres and Oceans.
E is for ECMWF, ERA-40, the EGU, and Exeter (geophysical and astrophysical fluid dynamics).
F is for Fluid (visit the Journal of Fluid Mechanics, Annual Review of Fluid Mechanics, or Physics of Fluids), and Florida State (Oceanography).
G is for Geophysics (visit the Journal of Geophysical Research), and for GFDL, Princeton.
H is for Harvard (Atmospheric Sciences), Hawaii (Meteorology and Oceanography), and Hokkaido (Earth Science).
I is for IFREMER (LPO), and IPCC (the Intergovernmental Panel on Climate Change).
J is for JPL, that is NASA's Jet Propulsion Laboratory.
K is for Kyoto (Geophysics and Radio Science Center).
L is for Laboratoire (visit LadHyX, LMD, or LEGI), Leeds (Applied Maths, or Earth and Environment), and for my old friends in the maths department at Loughborough.
M is for Meteorology (visit the UK's Met Office), MIT (Program in Atmospheres, Oceans, and Climate), and McGill (Atmospheric and Oceanic Sciences).
N is for NCAR, NOAA, and Northwest Research Associates.
O is for Ocean (visit the Journal of Physical Oceanography), Oxford (Atmospheres, Oceans and Planetary Physics), and Oregon State (Oceanic and Atmospheric Sciences).
P is for Planets. Find out more about The Nine Planets, and their atmospheres.
Q is for Quasi-biennial oscillation. Visit the informal tour at Kyoto.
R is for Reading (visit the Department of Meteorology), and for RMS, the Royal Meteorological Society.
S is for Scripps Institute of Oceanography (physical oceanography), San Diego (Mech + Aero Engineering), Southampton Oceanography Centre, and St.Andrew's (Waves, Vortices and Turbulence Research Group).
T is for Toronto, and the Atmospheric Physics group.
U is for UCAR (here is a list of member universities), UCL (maths department), and UCLA (Atmospheric Sciences).
V is for vortex street (visit here or here to see some vortex streets in the atmosphere), and for Victoria (Ocean Physics Group).
W is for Woods Hole Oceanographic Institute , the University of Washington (Atmospheric Sciences, Oceanography, Applied Math, or Applied Physics Lab), and the University of Waterloo (fluids group in applied maths).
X is for eXperiments (well, almost). Visit the Atmosphere and Ocean in a Laboratory site at Kyoto, or Peter Rhines' GFD Lab in Washington.
Y is for Yale (Geology and Geophysics),and Yokohama (home of the Earth Simulator).
Z is for Zurich. Visit the Institute for Atmospheric and Climate Science at ETH.
  Please let me know if any corrections or updates are needed.

Stephen Griffiths, 8th May 2009