Links to different Brewing Conversion tools and ingredient information can be found Below
Information on lots of different Yeasts Grains, Hops, and other brewing ingredients can be found here.
A Refractometer Calculator to convert to SG and calculate Alcohol content when using a Refractometer can be found here.
A refractometer cannot be used to accurately measure the Specific Gravity of Wort once it starts fermenting and alcohol is present without calculating out the effects of the alcohol. The link above provides a calculator that will compensate for the affects of the alcohol and provide you with more accurate SG measurements.
Yeast Comparison Tables can be found here.
Yeast Comparison tables to see the closest equivalency between White Labs and Wyeast strains
Visit Brun Water here.
Brunwater has resources to learn all about water chemistry as well as a downloadable spreadsheet to calculate out what mineral additions may need to be added to your water to achieve your desired brewing water profile.