40 CFR Part 136 contains the list of all approved test methods for NPDES and CWA reporting. Find the most current version here:
http://www.gpo.gov/fdsys/browse/collectionCfr.action?collectionCode=CFR

EPA Method 200.2
Download EPA 200.2 Metals Digestion Method in pdf format.

EPA Method 200.5
Metals Digestion of Drinking Waters

EPA Method 200.7
ICP Metals Digestions of water and wastes

EPA Method 200.8
Download EPA 200.8 Metals Digestion Method.

EPA Method 3031
Metals Digestion of oils, oil sludges, tars, waxes, and viscous petroleum products.

Method 3050B
Download 3050B Metals Digestion of Soils in pdf format.

Hexavalent Chromium
SW3060A

EPA Method 9010- CN
Download EPA Method 9010C for Cyanide Distillations in pdf format.

TCLP
Download TCLP Method 1311

Massachusettes EPH
Download the MA EPH Method for Extractable Petroleum Hydrocarbons

EPA Method 1604
Total Coliforms and Escherichia coli in Water by Membrane Filtration

EQL-0310-189- IML 2009
Acid Digestion and ICPMS Determination-TSP (Total Suspended Particulates) for Lead in ambient air