I am running my PC at a resolution of 800*600 when I change it to 1024*768 and visit LQ than I feel that the fonts appear too small(or may be I am not used to it), Do you feel the same too?

I guess LQ is using Verdana 10 pts , Which font and size should be used on webpages that will cater the need of both 800*600 and higher resolution visitors?

most sizes are defaulted to 11px, not 10pt, if you look at the css... but how big the fonts look kinda depend on the size of your monitor and such...

I said 10pts as when I opened a saved LQ page in Frontpage and It showed the font sizes as 10pts.
I don't know why as in the css the size has been set to 11pts

Can I define the font sizes in pixels without using CSS?

i did'nt knew that there was a difference between pixels and points and that answers my above question too.(just learning basics)

if you want them bigger in your browser (assuming you use firefox, most browsers should support it tho, all mozilla based ones should at least)

goto view->text size->increase

if you want it for a web site, don't bother, just use 10-12 as norm, as saying the size really doesn't do much good, in the end the browsers decide what size the text is, based on what kind of fonts there are (fixed texts are only one size, like a picture of an image that cant be resizes, so they only support a few popular sizes, scalable fonts can have any size, etc, etc)