I'm using the jQuery plugin Smooth Div Scroll on a site right now, and it's filling my needs nicely. The site is built on Drupal 6, and SDS requires jQuery 1.5, so some jiggery-pokery is needed to get all the right libraries in the right places. Drupal 6 includes jQuery 1.2, and the Drupal 6 version of jQuery Update only takes that up to jQuery 1.3. I had to mess with my theme's phptemplate_preprocess_page() function to make it all work. I don't think this is a common enough problem to bother posting about my specific solution, but here's the code I started with.

Once I was able to get it working on the pages of interest, Smooth Div Scroll has done a fine job.

The goal is a gallery with a smooth, horizontally scrolling image carousel, with thumbnails below for jumping directly to certain images. Smooth Div Scroll does this very well using its "moveToElement" method. The only problem is a distinct lack of smoothness — it just jumps straight to the image instead of animating.

I was pretty sure this wouldn't be difficult to fix. On line 384 of the non-minimized jquery.smoothDivScroll file, there's this line:

el.data("scrollWrapper").scrollLeft(el.data("scrollXPos"));

Just like it says, it sets the scrollable area's left position to whatever it's supposed to be directly, with no animation. To make it animate, replace that line with this:

el.data("scrollWrapper").animate({'scrollLeft', el.data("scrollXPos")}, 'slow');

Same thing, but with a "slow" animation. Nice!