Here is one app that gives birth to a new genre altogether. Auto Call Recorder does exactly what it says and what it has been developed for, i.e to record calls.
Developed by Roman G. the developers are very quick in their response and have done quite a neat job with the development of this app.
Auto Call Recorder is so streamlined, that the less is written about it the better it is. I have tried version 1.0.9 on a Samsung Galaxy S II and I have to say that it really works like a charm without any fuss. The User-Interface is very clean and integrates well with the Android ecosystem without breaking a sweat.
The Auto Call Recorder boasts of some very neat features, which helps users to the greatest extent possible. So, once the application is installed and setup, the app runs silently in the background and records every incoming call without any prompt. Well, if you do not want to record all calls, there is a Blacklist feature to block recording for certain contacts. Also, the app prompts you, if you would want to keep a recording after the call has ended.
Overall, the app packs in a lot while being free. Its more of a steal and should really help when verbal communication really needs proof. A great app and a must have on all Android devices, because you never know, when you would need it.