Do I have to do that in the code, or with the Arduino software?

Both. Have a look at the Serial I/O -> SimpleRead example in Processing. At the bottom of the sketch, in a comment block, is a simple Arduino sketch that sends the result of a digitalRead() over Serial. The example sketch changes the colour of a rectangle, but you can add your Minim code to it.

The Arduino detects the button press, and sends a message over Serial. You'll need something running on your PC that will receive the Serial data and play the MP3 file. A Processing sketch (http://processing.org), using the Minim library (http://code.compartmental.net/tools/minim/), could do that.

You risk damaging your Arduino connecting an 8 Ohm speaker to it without a series resistor.

Link?

Where did you even see this term?

I think he's still trying to do his homework assignment.

Where are alignLEFT, alignRIGHT, hideTop and hideBot defined or updated?

To me green is green, red is red & blue is blue

To me, green might be green, or red, or brown, and so might red. Blue might be blue, or purple, or green. Yellow might be yellow, or green, or orange. I hate resistor colour codes.

Before I move on, please describe a real-world scenario for this TelnetClient example.  how would I know whether what is a telnet server running daemon?

If you have a Windows PC, you can enable the telnet server service.

Why isn't this example using port 23 anywhere in the code?

Because it's written to talk to the chatserver Processing example sketch, on port 10002. You can change the port to 23, if you have a telnet server.

Try 74.125.224.72, or one of the others listed in these links.

http://compnetworking.about.com/od/traceipaddresses/f/google-ip-address.htm

http://toolbar.netcraft.com/site_report?url=http://www.google.com

That doesn't appear to be Google. I get it blocked as 'Suspicious - Placeholder'.

http://www.findip-address.com/198.105.251.46/whois

Handle   NET-198-105-240-0-1
Ref   http://whois.arin.net/rest/net/NET-198-105-240-0-1
Name   SEARCHGUIDE
OrgRef   Search Guide Inc
CIDR Length   20
Start Address   198.105.240.0
End Address   198.105.255.255
Type   DS
Description   Direct Assignment

Do you have a usb bluetooth driver library for the ADK? I know that Circuits@Home's libraries support some (not all) bluetooth dongles for their USB host shield, but I don't know if there is an equivalent library for the ADK.

You can use the R/C input option, and drive it using the servo library.

https://www.google.com/search?q=arduino+line+following+robot

Please advice how may I load the compiled file (HEX) to simulator.

I don't think you do. You load your sketch into the simulator's IDE, and run it from there.