The way i can getting user input is Read application as follow:
Read(variable[,filename[,maxDigits[,option[,attempts[,timeout]]]]])
But if i want to play multiple file instead of one file to get user input, it doesn't have any option! I can use Playback or Background to play files and then call Read application, but user can not input during sound play.
According to voip-info in Asterisk version 1.4, you cannot do that, but in 1.8, you can specify multiple sound files by separating them with the '&' symbols. (Playback and Background also support this method of playing multiple sounds)
I'm not sure if the feature is supported in 1.6 or not.