Kart racing is both similar and different from Auto racing. Similarities include types of venues. Differences include size (obviously) and approach to safety equipment. Additionally, Karting makes agressive efforts to bring younger drivers in a way that is difficult with full sized cars. Karting includes both road race (using shorter sprint courses and the larger courses shared with full sized cars) and oval variants (both asphalt and dirt/clay.)
There are two major sanctioning bodies for Karts in the US and Canada, and numerous clubs, larger and smaller.
The Kart Track Index on this web site lists most of the tracks where Karts run in North America. One caution: in its current form, it doesn't always distinguish between sprint course and road courses although it isn't too hard to tell (if it is listed as a "road course for Karts", it's almost certainly a sprint course).
Kart Safety equipment resembles larger car safety equipment in many respects, but also has significant differences.
Like drivers in big cars, karters wear full racing suits, helmets, gloves, and shoes. Neck braces are commonly required as well.
On the other hand, karts traditionally do not use roll cages or harnesses, prefering to let the driver go his separate way from the kart. Some oval facilities do run caged karts, however.
Sprint karts are run on small road courses ("sprint courses") that are usually not large enough for racing full sized cars (although autocrossers may sometimes run full sized cars on these in a time trial mode, one at a time.) These courses are generally paved, although there are a small number of short non-oval dirt tracks around.
These can be traditional or caged karts, not substantially different from Sprint Karts for the most part. These karts may run on the same ovals as full sized cars, although there are also a fair number of short (1/4 mile or shorter) ovals that are promoted specifically for karts.
Enduro karts are a very fast lay-down kart which run on the same full sized road courses as full sized cars.