RORO01  I can't understand. Why do we need this application? Safari already includes Private Browsing. Go to the menu bar under "Safari".  
(Version 1.2)

LOUNGE DELUXE  I emailed the developer and asked if he could make this script also work for Webkit. Within 2 hours I received a new script that did just that! How 'bout a responsive developer!

For all of you wondering what the point of this script is, stop wondering. This is a script that can make your computer life a little easier, period. I often forgot to turn private browsing on, now it's done automatically for me. That makes enough sense to me. If not for you, then move on and forget about it.

You can download Webkit PB and a lot of other useful free scripts at the website of the developer: http://tomx.890m.com/  
(Version 1.2)

NED SCOTT  So.. what's the point of this? Even for an apple script this is pretty pointless, and I'm trying to figure out why it's even coming up on MU. It's a script that does nothing more than execute a menu command.   
(Version 1.1)

DR. GIRLFRIEND  This tool is very handy. I can't tell you how many times I've uploaded intimate pictures of Monarch and me to our flickr account and forgot to turn on "private browsing" in Safari, then rush out, forgetting to clear the cache because we're too busy arching Dr. Venture. You can imagine the rest: those d-bag Henchmen download images from the cache and the next thing I know, I'm getting calls from every p3rv on Craigslist with a Harvey Fierstein fetish and a bottle of lotion.

Anyway, SafariPB is great! I use it with Launchbar and now it opens automatically instead of the regular Safari. I'm a busy gal and I can't remember to always manually turn on private browsing, so this little applescript is a lifesaver for me. Thanks, TomX!  
(Version 1.7)

ZANGIEF  Nice little script, I suppose– but wouldn't it be a little faster to just use the menu item with Option held down?  
(Version 1.1)

ANONYMOUS  Just negging out the bad rating below that was uncalled for.   
(Version 1.7)

DYSAN767  This works GREAT! Make sure Safari.app is in Application with Safari PB.app then load Safari PB.app -

Jesse  
(Version 1.1)

LOUNGE DELUXE  Works flawlessly for me. I asked several developers of pref settings utilities to add a similar function to their app, but all refused. Thanks a lot for this script!

Would it also be possible to publish one for WebKit instead of Safari?  
(Version 1.0)

NPTPRCHR  I installed it in the same folder as Safari and it doesn't work. Safari launches just fine, but it is not in "Private Browsing" mode. I don't know if I did anything wrong, but the one warning in the ReadMe did not apply, so I don't know what else I could've done.  
(Version 1.0)

RAJIVGOWDA3  I wish you had made the script editable ... any ways just for curiosity sakes I tried writing my own script to accomplish the exact thing and have posted it as editable script:)

here it is :

http://rajiv.homeunix.com/SpySafari.zip

just a fancy name :P  
(Version 1.8.2)