+1  A: 

You can use http://browsershots.org/.
This saves a lot of time :)

n00ki3
That's not client side.
Ronnie Overby
+1  A: 

I use Canoo Webtest.

Otávio Décio
+1  A: 

IETester is pretty good for IE testing.

Jon Galloway
+1  A: 

I've only recently discovered Adobe BrowserLab and have grown to love it!

From the website:

Supported Browsers and Operating Systems

* Firefox 2.X and 3.X (Windows XP and Mac OS X)
* Internet Explorer 6.X and 7.X (Windows XP)
* Safari 3.X (Mac OS X)

Viewing and Diagnostics Tools

Screenshots can be viewed in a single view, side by side view, or as an overlay view with variable transparency. Each viewing option features a zoom function.

Browser Sets

Browser Sets allow designers to customize, edit, and save a combination of browsers to test.

Aron Rotteveel
Awesome. This is the kind of alternative I was looking for.
Ronnie Overby