Due to lot of request, we have introduced "by pass silent switch" feature.
You can use "Auto Silent" app to disable or bypass iPhone Silent switch. You will get all sounds including ring, yeah including ring.
If your switch was broken in silent mode, it will restore all sounds, including ring. Then you can use Auto Silent app to put phone into silent mode.
The app supports iPhone 2G, 3G and 3GS and OS firmware 2.2, 3.0, 3.1
This app can also be used by those people whose silent switch is loose or accidently put phone into silent mode.
Also, there is provision to put phone into silent mode automatically using pre-configured settings in the app or according to appointments in iPhone Calendar.
There is provision to put phone into silent mode based on timer. This is useful for people who put the phone into silent mode but forget to unmute it. The app will put phone out of silent mode automatically once timer goes off.
More info at
iPhone Packers: iPhone dev team
The app can be downloaded through Cydia. You neeed to jail break in order to install Cydia. Search for "How to jailbreak iPhone" on google.