Currently, there are several places in the administration center about "Smileys of the moment" and so forth. What might interest you is that the packages, smiley sets, and themes that will be featured in these areas could even be yours!
Since the feature isn't done yet, this might be difficult to explain; in the future, these panels will feature popular items, as well as one random one that would differ on page view. So no matter how insignificant your modification, theme, or package is - your contribution to SMF will be noticed, and will get "advertisement" so to speak.
Of course, not just any theme, package, or smiley set will go in blindfolded, but this is our way of not only making it easier for forum administrators to see what's available, but helping people better appreciate your work, the work of those who contribute to the development of SMF.
The following posts will, in the near future, contain information about how you can make your own packages, themes, and smiley sets to submit to the Simple Machines Team so they can be shown on these "latest item" panels.
Making a theme package...
After you've created your theme, which is described in other places (http://www.simplemachines.org/community/index.php?topic=3194.0), you might want to package and let other people use it. The very first step is creating a "theme info" file.
A theme_info.xml file comes with the "classic" theme. Copy it over, and open it up. There're some advanced features, but we won't get to those here. Just change the fields you see (name, author, website) to the correct values... ignore anything you're not sure about, because what's there is most likely right.
The second step in this is actually packaging it. To do this, you will need some sort of utility that creates tar.gz files. There are several for Windows, such as:
You will then want to zip up the theme directory and all it's contents. Be careful, because some programs are shifty about this. You need to make sure that the archive does not include the theme directory itself. (in other words, it shouldn't be mytheme/index.template.php, but instead just index.template.php in the archive.)
Now you have a tar.gz file that should be installable from the administration section. We recommend you name it like so - mytheme_1-0.tar.gz (where 1-0 is the version number, 1.0.)
After that, you'll have to submit the theme to us. Right now, this part isn't ready yet - but at least you can package it ^_^.