Here are some links which may be useful:

The Periodic Table,  including all kind of details about the different elements (crystal  structure, lattice constants, etc.) can be found at the address: http://www.webelements.com/webelements/index.html

Fundamental Physical Constants: http://physics.nist.gov/cuu/Constants/index.html

Physics from Wikipedia, the free encyclopedia: http://en.wikipedia.org/wiki/Physics

Introduction to Modern Solid State Physics by Yuri M. Galperin, is an online text book on condensed matter physics: http://folk.uio.no/yurig/fys448

Principles of Semiconductor Devices by B. Van Zeghbroeck, is an online text book on condensed matter physics (with the emphasis on semiconductors): http://ece-www.colorado.edu/%7Ebart/book/contents.htm

Crystal Lattice Structures,  concise index of common crystal lattice structures. A graphical  representation as well as useful information about the lattices: http://cst-www.nrl.navy.mil/lattice/

Solid State Physics: Interactive Learning, java applets illustrating various problems in solid state physics: http://solidstate.physics.sunysb.edu/teach/intlearn/

Quantities, Units and Symbols in Physical Chemistry, the Green Book (second edition)

Periodic Table of the Fermi Surfaces of Elemental Solids: http://www.phys.ufl.edu/fermisurface/