Step 1: Free download avi to flv Converter and install it.
Step 2: Open this avi to flv converter suite Pro:

Step 3: Click
button to input avi files , batch avi to flv supported.
Step 4: under Profile selection: click download arrow, Choose: FLV video format (*.flv)
.
under output Folder , Click "Change" button to select the destination folder you want the converted 3GP to store. (the default folder is stored under file: c:\outputFolder\)

Step 5: Click
convert button to start convert avi to flv.
Then the Converting avi to flv process shall be looked like this

After successful converting avi to flv, the converted FLV files shall be stored on the folder you have previously selected.
With this powerful avi to flv converter, not only can convert avi to flv . you can also convert FLV to almost all other popular video formats. but all the process is the same, Just Free download and enjoy it.