Rewrite my urls in automatic and correct way

[eluser]jparent[/eluser]
sorry, I'll try to explain it better:

I have this:
http://wwww.myurl.com/controller/method/param1/param2

in my case:
http://wwww.myurl.com/news/categories/ca...id/perpage

and I want this:
http://wwww.myurl.com/news/categoryname

I need to pass id to the method because maybe two categories with the same name and different id.
I need to change the url with the routes archive or with code.

In other way I have this:
http://wwww.myurl.com/news/new/newid

And I want this:
http://wwww.myurl.com/new/title-of-the-new

The title in the database is like "title of the new". I need to change it to friendly url like "title-of-the-new"

I hope now its more clear. Thanks for your help.