Newbie at making a plugin – help needed!

Hi guys. 🙂

I just started making my plugin, and I would like some help with a thing, I tried aearching around the internet, but just can’t seem to find an exact answer, or else I dont understand it…

Oh well. I would like to make it so I can change some things in my widget, example an input form (I’ve seen in many widgets) so I can enter my username to somewhere, and then in my code (example) :

<iframe src="lalalal.com/something" />
– so “something” will depend on what I entered in the form.

And also someone to know how to make a page in the sidebar in controlpanel, so I can change some things too…?

Hope someone can help me or give me a good link to tutorial – tried to search alot after this.

Thanks in advantage! 🙂