Firstly, with a thread title like that, you're not going to get much help. It needs to be as precise and descriptive as possible(not trying to be mean, just helpful, and I understand your question is some what vague by nature).
Your first question can be achieved through CSS, jQuery, and JavaScript and the use of the ID and CLASS attributes in your elements. Basically you apply the onMouseOver (or something along those lines) function to modify the style (i.e.: color) of the other elements. jQuery is great for dynamically editing styles like this.
Your second question can also be solved through jQuery. http://docs.jquery.com/Tutorials:jQuery_For_Designers Has an almost exact tutorial on this subject. Browse the tutorials on www.jquery.com They are very helpful, and sounds like it's exactly what you need.