yes. A lot of people still use the screen resolution 1024x768. So for now it is still best to use any width below 1004px as that is usually the cutoff for that resolution.
yeah keep below 1010px - you don't want a horizontal scroll bar on any site - and with many people at 1024x768 resolution this will certainly create on. Also don't forget to take into account the slight margins on any browser and also the vertical scroll bar. With these things considered anything around 1000px is good to use. Maybe just stick with 1000px as its a nice round number
I will say go for it, once in a while you can forget 1024x768 screens & IE6 users. Just my humble opinion
And on second thoughts if you must support a 1024x768 resolution screen 990 pixels is the max you can go without having a scrollbar in IE. Some browsers will accept upto 995px but not IE, it will show a horizontal-scrollbar.
You might want to use a liquid layout, because msot desktop browsers are probably set up at 1024px screen with, but keep in mind that users might have sidebars installed (Google desktop sidebars, windows vista widgets, etc) that make the window max width less than 1024px. Also your blog might be visited via mobile devices that have very different widths.
For reference, of the 47,000 + visitors to one of my sites, just under 97% have screen resolutions of 1024 or higher.