This one is pretty good Click here
Lighter roasts: more acidic, suitable for plunger, syphon and filter. Reveals floral and citrus flavours
Medium roast: Some acidity - suitable for plunger and espresso. floral and fruity flavours
Dark roast: Low or no acidity. Suitable for espresso and stovetop. Usually caramel and chocolates
These arent hard and fast rules and you can expect variations depending on the bean, roaster and temperature profile.
I dont think there is any substitute other than working it out for yourself. Its all part of the fun/experience and, as youve would have often read on these pages, it is your preference. I find I enjoy espressos made from lighter roasts but I dont like much acidity.