blocked phone calls and messages on iphone 4

There is no such thing, and true number blocking can really only be provided by the service provider at the switch.
AT&T offers some call blocking features if you buy their parental controls package/service.
P.S. from a technical point of view, the phone has to allow the call to connect to first know what the number is. So-called blocking apps really just use a blacklisting approach. The phone still rings at least once, to allow it to collect the caller id information to compare to the blacklist. No handset can truly block a call by itself.
Message was edited by: Michael Black
2.53GHz MBPro unibody, iPhone 4 Mac OS X (10.6.6)

No, there are no apps. However, some carriers offer call blocking. So, have you contacted your carrier to see if this service is available? If not, you can always assign a silent ringtone to the number/numbers you want to block.
MacBook Pro

Thank you very much for the information!!
hp3434