will a 600W PSU power the following?

PSUs tend to vary widely in quality (particularly at the low end), and depending on the video card, current rating may be important as well. Some cheap PSUs may put out much less than their rated power at full load, and others advertise a high power output but can't handle the current draw that some modern video cards incur.

Most 600W PSUs of reasonable quality should be fine with what you describe, though.

This heavily depends on the model of the video cards. Most will list a minimum PSU requirement. You should be content with 600w if the cards are on par with HD 4850's or less.

I'd have a look at Newegg's Power Supply Calculator.

I usually refer to this PSU calculator and this PSU brand guide list