But why to take the headache, Will it really help you?
Yes, if you are a writer, blogger, graphic designer, programmer, developer indeed it increase productivity of almost everyone who use computer for more then one thing.

Really but How?
what a stupid question right? :P just kidding
Let me explain you with some examples :

• For Designers: You can open Adobe Photoshop on one monitor, and the design you are about to copy in another. :P
• For Developers: Write code on one monitor, while looking at the database structure on the other.
• For Support: Keep IM (instant messaging) , emails, other communication applications on one side and work on the other.
• For Blogging : While Writing a post on one monitor, open important points on the other which you don’t want t miss.

Let me tell you how setting up multiple monitors helped me.
I know you don’t want to hear my boring story but still I will share it. :D
When I was using a single screen,  half of my day was wasted in minimizing and maximizing windows.

How?
In Old days whenever I googled something. It was my hobby to open all the top ten searches. Just think once if you have all these processes running on you computer
10, 12 internet explorer windows. (Old days, thanks to tabbed browsing now)
5, 6 chat windows.
DreamWeaver, Notepad ++,  Adobe Photoshop, Windows Media Player, Microsoft Word and bla bla bla…
My desktop used to became so cluttered that I mostly get lost myself.

But now everything is organized.
Hurray! Boring part over, lets do some action
For connecting an external monitor, make sure your laptop have a VGA or DVI port (all modern notebooks have).
If your notebook don’t have a VGA, you can easily get a USB VIDEO ADAPTER to your laptop to connect another monitor.
My Compaq Presario has a VGA port and I have connected my notebook with HP LCD 2009f and I use my LCD as my primary display.

STEPS TO SETUP Muliple Monitors ON A LAPTOP RUNNING WINDOWS 7

1. Just connect the VGA or DVI Cable to its port
   

   VGA Cable and VGA Port

   Note for Blondes: if you are thinking to connect a DVI Cable to VGA Port, then “May God Have Mercy on You”. (no offence :P)

2. Right Click on desktop, then “Personalize” .
3. In the Personalization window Click on ‘Display’ on Bottom Left.
4. Now From Top Left, Click on Fourth Option  “Change Display Settings”
5. Now in “Multiple Displays” list box select “Extend These Displays”.
6. Click “Apply”
7. Now if you want to use your monitor as main display Select Your Monitor Name in ‘Display’ List and select the “Make this my main display” check box.
8. Click OK.

Now drags windows between monitors and adjust stuff according to your satisfaction
I hope this small effort of mine helps you to increase your productivity.
Yeah yeah you are welcome. :P