Actually, freezing any sort of alcohol, vodka and gin included, affects the flavor of the alcohol. Kind of no point in drinking it if you don't like the way it tastes au natural.
A gin or vodka tonic should not actually be served in a rocks glass, but in a tall glass (not a pint, but a tall slim glass, like a collins glass). 1 1/4 oz (one jigger) of gin or vodka over ice, fill glass with tonic, garnish with a twist (Peel and zest) of lime or lemon. One lovely way to punch up the effect of the garnish is to flame it... It takes some practice, but you essentially hold the very tip of the strip of zest and light it on fire, dropping it over the drink as it lights... The fire and heat release the oils in the zest, giving the drink a sharp lemon or lime flavor.
Because gin is essentially a distilled tincture of juniper berries, there are theories that if you shake it (rather than stir it), you "bruise" the gin, making the distinctive evergreen flavor stronger and sharper. *shrugs* I can't stand the stuff myself, so I couldn't tell you. I do know that amongst my gin drinking customers, there are definite opinions regarding the taste of their gin. Conversely, shaking and stirring do not cause any noticeable difference in the taste of vodka, so it doesn't matter if you shake it or stir it, except that stirring it (for a martini) regulates how much the ice melts as it chills the vodka, resulting in a much more balanced martini, without too much water diluting the alcohol.
Give me vodka any day. *grins*
Anyway,
Webtender has some pretty cool drink recipes, and its pretty easy to use.