Help! Simple question from an inexperienced web designer

Help! Simple question from an inexperienced web designer

I'm using this http://www.queness.com/post/3036/create-a-custom-jquery-image-gallery-with-jcarousel (where all the code in question is located) image gallery on my website and having a lot of trouble having it centered. I've never coded with jQuery before and obviously just copied the code. I stumbled around a bit in it and changed

#slideshow-main {
      float:left;

to float: center

This just pushed the carousel on the right onto the next line. Help would be very appreciated. I can upload the zip of the site if it is helpful.