"Actually, I cannot use shared objects because I want some other application to use the info of text file."
"So, Janus-Flash seems a good option for now. I will lokk forward to use it....in between, can you please put some light on the communication that happens between Janus-Flash or some few links about the same..."
Janus-Flash encapsulate a SWF file in an executable EXE file allowing system calls to Windows OS.
Check this forum : http://www.janus-flash.com/forum/index.php?board=15.0
You just need to install Janus-Flash as a Flash Component,
And use this code :
ssp.filesystem.File.appendText("HelloWorld !", "myFile.txt");
Compile your SWF (Flash Lite 2.1 only !)
Compile your EXE using Janus Installer > Pocket PC
Launch exe on your phone, this will work.