Rather than doing it one by one, why don’t you just use the services provided by Browsershots (http://browsershots.org/).

Browsershots makes screenshots of your web design in different browsers. It is a free open-source online service created by Johann C. Rocholl. When you submit your web address, it will be added to the job queue. A number of distributed computers will open your website in their browser. Then they will make screenshots and upload them to the central server.

The site also provides a queue list so that you can have an idea how long will it take for you to get your screenshots. Since the service is free, a number of developers actually uses the service so it’s not going to be a real time thing here.

You can also view a list of computers that are used to provide the service and a list of sites submitted that are to be serviced.

You also have the option to preview the website design in browsers with or without Flash, Java and JavaScript.

Have Fun!