is to run a search for 'java tutorial' or 'Flash tutorial' etc. You'll get dozens of returns. I'm not an advocate of taking structured courses, I think it's better - and certainly more fun - to teach yourself by practising. By all means read tutorials, and then try out your newly-acquired knowledge on a site of your own. All ISPs provide you with free webspace, so you have a ready-made practice ground. You'll see your successes and failures in real time, on the web, which is by far the best way of doing it.
When you're stuck you can always come here for practical help and encouragement, and we'll provide you with honest opinions on your design skills.
Not everyone has natural design ability
but design principles can be taught or acquired. A good designer could look at a hundred web sites and make improvements to 90 of them, so don't feel you're in a minority when you say you're not too good at designing. You'll pick up ideas from other sites, and add some of your own. Gradually you'll learn what looks good and what doesn't, and your site will improve as you go along. It will not be a rapid process, but your time and effort will be rewarded - stick at it, even when you appear to be getting nowhere.