Blacklist for iPhone is not available on most iTunes stores, but it can be found on a few download sites. According to the publisher, Blacklist for iPhone allows you to block calls and texts from any number, and suppresses the popup previews for those numbers too. Once you download the app, it installs like any other, but you need a unique ID number and a password to activate it (which costs you $1.99).
The Blacklist for iPhone app has a simple enough interface allowing you to control how the app works. For example, to block a particular number, you choose the number and the behavior associated with it. To suppress calls from that number, you can simply have the call routed immediately to voice mail, provide a busy signal, or accept the call and hang up immediately. You can choose the appropriate behavior for each number you blacklist. When that person calls, there's no indication on the iPhone that the call has happened at all unless you route to voicemail. For SMS messages from a chosen blacklist number you can simply suppress them entirely or send back a custom SMS to those callers.
Blacklist for iPhone works as expected, and provides you the ability to control who calls or texts your phone and gets through. The blacklist concept is one most people understand from call blocking technology, and Blacklist for iPhone is quite easy to work with. Tracking this app down is the hard part.