Maybe this is an example of the two major problems with foruns today. The first is the "ask first, read later" philosophy, the second is the trolling, even if isn't the intention.
The fist step to solve this two problems is to read, read a lot. First you need to understand the tools you are dealing with, learning the capabilities of the tool (Arduino is a tool not a end in itself), how to make it do what you wan't it to do, the lingo (words used in a specific way) of the community, etc.
If you study first and ask questions later probably most your first questions will be gone!
Can you (faziefazie) see what is you first error? Lingo... Libraries in Arduino lingo are "packs of commands" to make Arduino programming easier, to save time and lines of command: what is the logic in reinventing the wheel???
You asked for libraries... There is lots of shields to do the arduino recieve commands of a computer via a lot of channels (USB, Ethernet, Wi-Fi), and probably there is a librarie for all these shields, but you put the "cart before the horse", and this situations usually irritate the older members for a simple reason: shows that somebody want to do something without read about it first.
The second problem coul'd be solved with a little thinking before typing. Ok, the question was "stupid", but if you, PaulIS, answer with in a constructive manner, maybe the newbie will understand his error and stop questioning "stupid" questions!
You are here since 2008 and have more than 63k posts, probably with a lot of arduino knoledge and a vast forum knoledge too! I'm the newbiest of all the newbie, but I'm seeing this kind of "conflict" in any forum that I go, and maybe because of my age this kind of situation in witch nobody gains nothing is starting to irritate em a loooot, keeping me off of foruns with lots of potential knoledge share, but with less than good forum dynamics.
And for the faziefazie, be aware that probably isn't good to read that your question are "stupid", but aways try to read between the lines. If you think a little you will see that or you can't express what was your doubt or really don't understand what you need to do what you are trying to do, the need for a software to send arduino a command, etc.
Ok, for my first post it was long, boring and even off topic... Let's call a day!
And sorry for my english, I'm brazilian and read a lot, but don't write in english very often.