php help needed

Hi,

I face a problem with a hyphen in a string..
eg:many strings in the sentence are like eg:cars-and-trucks---are--fast-----sometimes

So i need a script which will make it ascars-and-trucks-are-fast-sometimes .

The script will remove multiple '-' from a string. I there is more then one '-' (minus the quotes) in a row, I want to string output to remove the extra connecting '-'.

Thanks ee,
akiles