Getting around town
Dude, public transportation in Indy, such as it is, is scary. You really need to have a car. There's just no other way of getting from A to B. I-465 is brilliant. Visiters-it's just a big circle around the city, so you can't get that lost. Indy roads are perpetually under construction, and snow removal in winter is...entertaining.
By plane, you'll fly into Indianapolis International Airport on the West side of town. Actually, you'll land approximately five miles from the airport and just taxi around in the plane the rest of the way.
By car, more major highways run through Indy than anywhere else in the US. Once you hit I-465, the road signs are pretty idiot-proof.
Gotta Have Wheels
Not having a good reliable public transit system is something I really hate about home. If you want to go anywhere, you really need a car. There are some exceptions...
Staying in the Downtown area, you can walk to any number of shops, bars, clubs, sporting events, restaurants, etc. Broad Ripple Village is fun to walk around, but there are no hotels of which I am aware.
Otherwise, you will need a car. Driving in Indianapolis is easy. At worst, if you need over, or cut someone off, just wave. 9 times out of 10, they'll wave or nod back.