Yes.
High School Musical 4: East Meets West
On April 8, 2008, Disney Channel Worldwide President Rich Ross stated that script was being written for the fourth installment of High School Musical.[24] However since Zac Efron and Vanessa Hudgens' characters have graduated and headed to college, they will not be reappearing. The filming will be done by choreographer and director Jeffrey Hornaday and will debut on Disney Channel in the fall of 2010. Casting is underway for the fourth installment, which is set against the cross-town school rivalry between the East High Wildcats and West High Knights.
From Wikipedia

I don't think so they have already graduated!!!

yes. it comes out in august or september.

yes, defo but Zac Efron isnt playing Troy this time :( :( :( :(
i cant believe it

Okay, before you get too excited, this Disney project is slated to appear on....television! So now, it's full circle. The once-Disney TV franchise which had a fling in movie theaters last year is now back where it all started...TV.

Here's more info for "High School Musical" fans:

1) Goodbye old cast, hello new high schoolers! This time, it's going to focus on East High Wildcasts' rival across town know as West High Knights!

2) So no Troy (Zac Efron), Gabriella (Vanessa Hudgens) and company, but Peter Barsocchini, the screenwriter behind the first three films, is back for the fourth installment.

3) Look for this on the Disney Channel in 2010. I know, that's a bit long, but you can watch the first three films over and over again, until the brand new HSM4 :happy »

No