To detect the lib vulnerabilits, use the com.zimperium.stagefrightdetector from the market.
Attention: you need root privileges to make those changes - without root that app wont work.
The tool can not determine if your stagefright components are already patched, but if you did not receive an update after 08/01 you probably want to disable the components to be not affected by the current bugs.
You can disable the components with the other app "Stagefright Disabler"
If you have problems using the app - please write me an email.
[root] Stagefright Checker
This app has access to :