Question: Is there any way to save crash log while apps is crashed and also apps is launched at that time Mail Dialogue is display to send the mail with that crash log???? so please tell me any link or any idea to develop this functionality in iPhone...

Thanks in advance

Answer: 
I recommend [QuincyKit](http://quincykit.net/). It is open source and you'll have to setup your own server to collect crash logs.
Crittercism worked for me
It can be implemented in few minutes, which is easy and great.

Crittercism supports instant crash reporting to your mail(setting up server is not required)
Detailed report generation which includes the line number where the crash occurred.

Following links helped me:

[Crittercism](http://www.youtube.com/watch?v=ONp2S9USMNY)

**Note:** Adding DSYM file is recommended(which is responsible for showing the exact line number where crash occurred)

See [this](http://www.youtube.com/watch?v=i2hv35MisgM)