What programming skills will I need to write a WP plug-in?

I am looking to write a plug-in for wordpress to use for myself and as a free resource to my readers. What kind of programming is required to write a plug-in and how difficult is it?

I know I have not told you much about the plug-in itself but I think it is pretty basic and is largely just for use by the blog owner. Not used to change the blog at all but rather for the bloggers use in the admin area.

Any idea of the programming required would be great. I know good places to learn programming, like W3C, but I am not sure what kind.

 

For backend stuff you'll need to know PhP and possibly MySQL (depending on how you're planning on saving settings).

For any kind of display stuff xHTML/CSS is a plus.

Far as WP Specifics, its all detailed here at the wordpress.org codex

 

best answer by kblesinggr. you are absolutely right.

 

You need to learn the Wordpress Plugin API.
You don't have to know all the Functions and Template Tags but it helps.