I have some text in Photoshop & it's set to "crisp". When I put it on my site it doesn't quite look the same.
Does anything exist in CSS yet that I can use to make it crisp? Or not?
Or do you have any suggestions to achieve a similar effect?
Not only is it not possible, but different browsers on the market enforce different antialiasing settings, meaning that you can't get consistent results, even if they are not what you want.
For a good article on how the various browsers deal with font rendering, I'd suggest reading this: http://blog.typekit.com/2010/10/21/type-rendering-web-browsers/