In firefox the is non-antialiased text(Antialised text blends with background around edges to make it look smoother), but in internet explorer there is. Is there a way for my website to have non-antialiased?

I am using HTML with an external CSS sheet.

It is actually TEXT you're using or is an IMAGE of text ? Firefox treats REAL text no differently than IE.

Have you got a url so we can see it ?

I am using text, not a picture on my website. Here what I meant:

Those are both arial size 12. The second is antialiased, the first is not.
I want it to look like the first one on any browser. Is there a certain font like that, or a way to tell the browser no to AA?

Assuming you're on a Windows box, then you are running into a windows setting that does 'font smooothing', it is the most likely culprit for the difference.