Been using dropbox for a while for saving arduino sketches across multiple computers.  There are no real gotchas and I also use it to share code with others.

I did use Google Drive but I'd have issues with it.  Sometimes it doesn't always sync all the files for me.  It's a shame because my Google Drive is much larger than my dropbox.

I am sticking with dropbox because it seems to always work.  If Google drive was as robust I would probably move over to it.

For parts never bought from Aztec but generally will buy from Mouser or Newark/Element 14.  

Sparkfun is one of those places that will easily over charge you if you are not careful.   Also always read the comments of their products. I find a lot of people end up pointing out deficiencies in their design which often leads them to coming out with a new version of their product somewhere down the line.

Not bad mouthing them, it's just the way it is.

Did you try the tutorial on the official Arduino website?

http://arduino.cc/en/Hacking/LibraryTutorial

Personally I would use Xbee. 

Using Xbees is as simple as calling Serial.println().  If you are already sending data via USB I assume you are just making the same calls.

The cheapest shipping to Croatia is 15 dollars, so no thanks.

eBay is my only option and I'm looking for reliable Micro or Lenonardo board.

Surprised you cannot simply order direct from Arduino in Ivrea, Italy.  You are not that far away from there.   They sell Micros for €18.

The Big Bagpipe has a number of arduinos connected together  http://www.thebigbagpipe.com/home/concept

At one time there was a  "dual core" DIY Drone http://diydrones.com/profiles/blog/show?id=705844:BlogPost:40459

Someone also made an "ExtraCore library for Arduino"  http://hackaday.com/2012/08/31/dual-core-arduino-for-more-pins/

Adafruit sells a Micro for $25
http://www.adafruit.com/products/1086?gclid=CKKl9v--qbUCFQPd4AodLCEADg

Actually this was posted on Adafruit  recently  Arduino MK802 Based Mobile Web Server Robotic Platform Controlled via javascript with node.js http://www.adafruit.com/blog/2012/12/24/arduino-mk802-based-mobile-web-server-robotic-platform-controlled-via-javascript-with-node-js/

One way you could do this is to mount an Android phone that controls an Arduino.  The phone could also run a web server app that serves up all the html5/javascript/whatever goodness he desires.   

There are tons of examples of Arduino's being controlled by Android phones  (MIT for example:   http://appinventor.mit.edu/explore/stories/my-droid-robot-controlled-app-inventor.html)

Not saying this is the best way, its just a possibility.

Hey Learning can you post a pic of your Uno??  I am curious if it has the other 'features' of a fake arduino such as the chip markings sanded down.

You should return it to CE-Compass.  They have a 30 day return policy and a 15% re-stocking fee but if you prove it is a knock-off I think they might wave that (assuming they are reputable).   If you decide to return it let us know the outcome.

Well, excuse me for posting.

My post wasn't directed at you.  Don't take it personal.  It's just if you have red led's you more than likely got a knockoff Arduino.

I'm all for Arduino clones... just not ones posing as "official Arduino".

[Red LED's]

Red LED's did you say??   Play "Spot the Fakes" at Spotting Arduino Clones http://www.cmiyc.com/blog/2011/12/26/spotting-arduino-clones/

Here's a hint:

Don't we wish, maybe 100kHz

Hate it when I do that.   

Otherwise,  I would suggest Visual Studio,  for which there is a free version,  or at least there
was about a year ago when I installed it.

It's still free but after 30 days you have to register for a license ID.  It is not bad and the VS2012 has part of C++11 implemented.

I have no clue because you did not post code.   However if you want to get the Ping sensor to work there is an example code that comes along with the IDE for that.

In the Arduino IDE menu click File -> Examples -> 06.Sensors -> Ping.

This code assumes your Ping sensor is hooked up to digital pin 7.  If it isn't then scroll to the line that says:  const int pingPin = 7;

Change the 7 to be the digital pin you connect the Ping sensor to.

As for the code for the Arduino Motor controller look at this tutorial:  http://www.instructables.com/id/Arduino-Motor-Shield-Tutorial/?ALLSTEPS