I can only advise you NOT to try designing your own card from scratch, unless you have a reasonable amount of serious design training. It's harder than it seems to come up with something that looks professional, and the fact that you're working in limited space only makes it harder.
Assuming you're not a trained designer, you'll have more than enough work cut out for you trawling through the various printers. (Google "business cards" and you'll have loads to choose from.) You'll need to browse through their templates and also consider what they offer for what price, and you'll probably have to end up compromising somewhere.
Before you start shopping for business stationery, it's vital to decide the sort of feel they should have. What's your approach, and what's your personality? I think you mentioned in an earlier thread that you go for the strictly scientific approach, "demonstration of the powers of a properly trained human brain". In which case your cards should give this sort of feel. A symbolic head or brain might be good, or something with a scientific feel like gridwork or graph lines.
You should like the design -- which helps ensure it matches your personality -- but never choose a design just because you like it. It's your branding, and giving off the right message comes first.
For instance, I've recently taken the plunge and ordered some cards from Vistaprint. But I wanted something rather spooky and mysterious, so eventually decided on
this design of swirling smoke. It suits me, but wouldn't work at all well for your scientific style.
Note the large amount of information that can be put on this card. It's much too much. I only have three lines on mine (a large nom de guerre, and a smaller real name and e-mail address) -- because, not being a pro, I don't want to give out a phone number.
It took me days to settle on this design, and an afternoon to get the text exactly right. I changed the typeface to a script, changed the sizes, and moved everything around against the smoke background.