American Citizen looking to move to Serbia

I would suggest you talk to proper official channels about this...US Embassy in Belgrade would be my first choice. I went there couple of times and the personnel was helpful and friendly.
serbia.usembassy.gov
Good luck.

How to get there? By plane, car, train, bus... horse, walking... teleportation? There's no civilian airport in KG, so if you like planes - land in BG and take a bus to KG.
How to stay? Join some college maybe. Start working. In fields (crops, fruits, etc) if you don't have any profession and are so desperate.

lol. well thanks both of you for your answers. there are options with the us embassy, however not really available to me at this time. Also, I have already recently taken a trip to Serbia. Stayed there with a uh... "friend". Took the train from Romania (where I actually was with a friend) and from Belgrade took the bus to KG. Spent a couple nights in hostels and such as well. Was quite the enjoyable experience. Aside from my personal reasons, I realized I seriously love Europe. A lot more than being here in the US. And although I have ties to Serbia as far as certain people go, I enjoyed the general atmosphere there than any other place I've ever been. My plans already included a plane to Beo, and a bus from there, so Ive got that set, it was just a matter of me trying to get there as soon as possible with as little resources as possible. However in recent days I've come to pretty much have to accept what I thought would be the outcome. Ive got to work my way to it it seems lol. The hope of going out there once more on a whim is still slightly there, but things seem a lot more now like I'll need to make use of my patience. However. If anyone else finds they have something useful to say, please feel free. Thanks Again all.

if you're interested in a long-term life abroad, I highly recommend finishing out those years of college. Maybe you can figure out how to do it abroad, maybe you've got to do it in the US, but if you're serious about getting out of the USA, having a degree will make you much more employable. If you're trying to move on your own (and don't go the student visa route), the most likely way you can make it happen is to get a work visa. Having SOME kind of credential will help you get that tremendously.

Believe me, I understand the yearning to Not Be In America Anymore but you've got to offer your country of choice something in return for being allowed to reside there. Even if it seems like just a piece of paper to you, a degree adds some value when you're filling out those visa application forms.

I have an interesting idea. If you are a student you may use AESIC for student exchange. Several years ago my friend from India spent a year in Srbija, in Kragujevac using student exchange. You may try that.
Greeting from Kragujevac.

I know of a business opportunity that just opened up in Serbia if you would be interested in owning your own business. There is definite potential for growth.

@amymsou: I am ashamed to say (as a Serb) that doing business in Serbia is anything but easy... Way too much bureaucracy, extremely high taxes for this or that, way too complicated procedures etc. However, once (and IF) you overcome that, you have no major problems.