I'm using compressor which come with Final Cut Pro. It works well enough but doesn't have a lot of options for Mpeg-1.
I have been thinking of getting Sorenson Squeeze which is suppose to give you more option when setting compression on Mpeg-1.
http://www.sorenson.com/solutions/index.php
I really wish Mpeg-4 was more accepted but it isn't so I do Mpeg-1.
This is what I'm using for setting these days.
Audio Encoder
Format: MPEG
Sample Rate: 44.100kHz
Channels: 1
Bits Per Sample: 16
Video Encoder
Format: MPEG1
Width: 320
Height: 240
Pixel aspect ratio: default
Crop: None
Frame rate: 23.976
Bit rate .6Mbps
Deinterlacing
Algorithm: Odd
Noise Removal
Apply To: Chroma Channels
Iterations: 1
Algorithm: Replace
Watermark
Position: Lower Left
Scale By: 0.400000
Alpha: 1.000000
File Name: /Users/terri/Jobs/copyright.psd