From the Microsoft Expression Encoder download site:

“Microsoft^® Expression^® Encoder, a feature of Expression Media, offers encoding, enhancement, and publishing of rich media experiences to Microsoft Silverlight. “

Features Include:

Better Encoding

VC-1 advanced authoring SDK integration: by adopting the new VC-1 authoring SDK, Expression Encoder 2 is able to author better quality video faster. We’ve exposed a set of presets for tuning the encoder as well as detailed settings with comprehensive tooltips for the advanced compressionist.

New profiles, and video codecs for streaming media: Encoder 2 supports a number of new modes and codecs including Quality VBR, WMA Pro (stereo), WMA Lossless, 24 bit audio and audio/video encoding stream selection.

• Improved MPEG source support: We now include an MPEG 2 decoder in the product to give a consistent story across platforms. The decoder we ship supports transport streams (so you are able to work with sources that originated from HDV cameras. Seeking performance and accuracy has been greatly improved.

The FLV file format is supported, but FLV files will be shown as progressive download only. Ultimately, this means that users will not be able to fast-forward to any part of the video that hasn’t been downloaded yet. For small files (under a minute long or so) this is not that noticeable. But if you wish to provide true streaming with longer videos, consider
having GravityLab encode and host your videos as Windows Media and Quicktime. This will ensure that your audience is receiving the optimal experience with your content. Are you absolutely convinced that you want to use flash? Contact us for a custom quote for true flash delivery using the Flash Media Server.

GravityLab Multimedia offers several mobile video hosting plans, and many of our customers ask how they can create .3gp video files in order to stream the video to 3rd generation cell phones.

For this tutorial you will need a short clip of uncompressed video, including audio. You will also need Apple QuickTime Pro. You can buy a QuickTime Pro serial directly from Apple. Entering the serial number into the QuickTime player activates additional features in the software, including the ability to encode video to a variety of formats. See the “Buy QuickTime Pro…” option under the QuickTime player’s Help menu.
Once it is installed and running:

1. Load the uncompressed video clip using the player File > Open File… menu option.

2. Click on the File > Export… menu option.

3. Under the Export option choose “Movie to MPEG-4″, then click on the “Options…” button beside the Export drop down menu. (If your cell phone only plays .3gp video files, choose the 3G menu option instead of the MPEG-4 option.)

The key options are “File Format” and “Image Size.”

4. Choose MP4(ISMA) as the file format option. Although you probably will not know if your mobile phone is ISMA (a standards organization) compliant, try encoding with this option. If your device fails to play the file, try encoding with plain vanilla MP4.

5. Set the image size to the video resolution of your cell phone. If you choose the wrong size, your video may play and you will hear sound but it will have no image.

6. Select the Audio codec by clicking on the drop down menu at the top of the screen and choosing “Audio.”

7. Set the audio options to the following:

8. Upload the file to your cell phone and try to play it.

If your phone chokes on the video file, load the uncompressed file back into QuickTime Pro and try different settings to optimize the file size of the video.