Can I edit SiteGrinder pages in DreamWeaver or GoLive?
Yes, in fact SiteGrinder generated pages are much easier to edit in tools like DreamWeaver or GoLive than pages generated by hack-and-slice oriented tools like Fireworks or ImageReady. Further, one of SiteGrinders design goals is to exactly target tools and users who might wish to edit the pages after their initial creation.
When you open a SiteGrinder created page in DreamWeaver or GoLive it'll look pretty much just like it does in your browser. And when you look directly at the HTML code that SiteGrinder generated you'll be met not with a soup of non-sensical markup, but instead a rather modest HTML file that has labels and ids that clearly match your original Photoshop layer names. Plus, you'll find all your "true text" in Photoshop has been dutifully reproduced in the HTML, ready for you to continue editing.
SiteGrinder inserts no custom or proprietary markup, uses very little javascript (and when it does, you'll find those scripts carefully commented). As you use SiteGrinder you'll learn that its output is very easy to predict, which lets advanced users easily prepare and perform cool tricks like making data driven pages or leverage liquid layout techniques. Look here, for a breakdown of SiteGrinder generated HTML and CSS.
SiteGrinder and Photoshop make an excellent team for creating and generating websites, but neither are especially good tools for site maintenance. Tools like DreamWeaver, GoLive, and emacs are all great tools to use downstream of SiteGrinder and you'll find that all of them play very well together.