are the Arabic languages mutually intelligible?

<<I've heard that difference between Arabic in different countries is roughly comparable to the difference between Spanish and Portuguese. Do you find this to be true?>>

Even if Spanish and Portuguese are brothers, I can't understand anything of what a Portuguese is saying. However, I can understand perfectly written Portuguese.

Portuguese understand Spaniards more than Spaniards understand Portuguese. That's because Portuguese phonetic is quite difficult.

Handwritten Arabic (as opposed to printed script in a book, banner, monument, or electronic screen) is more streamlined. For example the "points" or "teeth" on letters such as [Sin] become a long curve. Two dots become a dash and three dots are written as a circumflex.

Here is a good example of the alphabet:

http://home.comcast.net/~torcwin/arabic1.htm

Here is an example of the ligatures that get created:

http://home.comcast.net/~torcwin/arabic2.htm

(the ligature on the left is created by adding the two letters on the right)

Here is a good introduction to calligraphy and styles of script:

http://www.islamicart.com/main/calligraphy/
http://www.islamicart.com/main/calligraphy/styles/index.html

"I've heard that a man from Morocco can't understand a man from Iraq at all.

I think there's only ONE Arabic language, with a lot of varieties. I'm not sure, though. "

Cos most people in Morocco speak French.