You could try kuaidial which similar to iBlacklist. I installed it for a short time before purchasing iBlacklist and can confirm it does work well.
I ended up choosing iBlacklist because it's well known and supported. Looking for kuaidial reviews didn't turn up too much info. It's free with no ads which is nice, but also made me cautious since it can see your contacts and selling information is a popular thing.
I could be overly paranoid and completely wrong. The source code is posted online but I don't understand coding so it's no help to me. Also, why isn't a free and functional blacklist app more popular?
Here's the repo if you're interested.
http://kuaidial.googlecode.com/svn/deb/