How to get rid of a lisp

How the help can I get rid of my lisp I hear it when saying words like physics

Speech therapy does the trick, look into it.

shouldnt there be a speech teacher at every school?

practice your s's a lot...I don't know

There should be a speech teacher at your school.
if not you can defiently find someone in a phone book. or ask your parents if they have one on there health care plan.

I dont have speech teacher at my school and speech therapy well my sis had that but it didnt work well she didnt go for a lisp and plus speech therapy isnt covered in our insurance

I know a good lisp exercise for anyone who is willing to try it. I read this on the internet and it's actually pretty easy. I am 14 and it's actually getting rid of my lisp! Anyway here's all you have to do: Stick a pencil under your tounge and then bite down on the pencil while it is still placed under your tounge. Try to center the pencil as close as possible and use an unsharpened one in order to have a better grip with your teeth. Then start practicing saying words in sentences. Make sure you're reciting the words/letters that you have trouble pronouncing. Hope it works!
P.S: I read magazines and books out loud while doing this. it gives your tounge a wider variety of words and sounds to work with on repositioning itself!

Here is a video that outlines some excercises to get you going. It is very professionally done.

http://www.youtube.com/watch?v=Jc8jEvC7jHs

Hope that helps