It depends as much on computer spec as browser software.
The page jerks ever so slightly in IE on the laptop I'm typing this on (Mobile Athlon 64 3000+, 2GB RAM, 64MB GeForce graphics) but my main desktop machine has no jerkiness whatsoever.
Regardless of the scrolling you might want to look at the software you're using for your web authoring, or the way in which you're structuring the site.
I've not looked too closely but your page code is vast and appears to be from Microsoft Word or Publisher. Neither program does a good job of web work and I can't help wondering whether at least some of the problems with scrolling could be down to that.
Example: your top image of the word Millie takes about 36 lines of awful code. You could just as easily do it in one.
Each subsequent image is wrapped in lots of position:absolute and VML junk that doesn't need to be there, not to mention the WordArt...
If you have FrontPage you should use it for creating and editing your web pages - Word and Publisher really are poor cousins when it comes to web editors.
I could probably reduce your page code by about 90% (maybe even more) and still give you the same look and feel - it will also probably cure some of the problems you are seeing.