Making small changes to the current theme shouldn't that tough at all if you're familiar with HTML and CSS but it would be a good idea to learn the basics of PHP.
You can easily edit your theme by opening the theme folder and making your changes there directly or you also have the options of making the changes via your Wordpress Admin Area.
If you're wanting to learn how to make your own design / theme for wordpress you can start from hereTheme Development « WordPress Codex
remember to make backup copies as you go along. sometimes the code we put in doesn't do what we thought it does. :blink:
how easy is it to cleanly slice a psd and have it work with wordpress?
