Script for converting FLV to AVI, MPG, etc

I found some information at Convert Google Video FLV’s into AVI, MPG, etc…in LINUX on converting videos from flv to other formats. So I decided to automate the process a little so I wouldn't have to type in the command constantly. My script accepts two parameters separated by a white space character: the video you wish to convert & the destination file. Here's my code

#!/bin/sh
ffmpeg -i $1 -ab 56 -ar 22050 -b 500 -s 320x240 $2