Like many web developers before me, I've become a conscripted webservant in my wife's quest to launch a website - Rachel's setting up a store for high end children's clothing. She's got an incredible eye for design, which makes her one of the toughest clients I've had.
When her sister viewed the site in Safari the links all appeared red. Strange, as the CSS bade it otherwise (hello, LoVe / HAte rule). Well, iCapture came to the rescue. I didn't have to sidle up to the genius bar with a wad of cash; I just entered the URL and saw a screenshot. Be sure to chop the http:// off your URL - the site chokes on that, and it's also got an address length limit that caused problems deep into my DotNetNuke site. Still, a nice way to spot check Safari rendering on the cheap.
And while you're at it, check out ieCapture - the easiest way to see how your site will render in IE7. I suggested this kind of thing to the IE team at Mix06 and haven't heard anything since, but Dan Vine's got us covered.