I don't know of a way to check Yahoo email on the television, and the short answer on that would: no.
The PC Share Manager software is for streaming content from your PC to your television. This can be used for pictures, music and video.
It may not be picking up any compatible formats. Are your music files in mp3, or .aac? The television's DLNA will accept mp3 file formats, but not .aac.
I recently purchased the Samsung UN46B8500 LED and noticed it includes Yahoo widgets, but was wondering if I am able to check my Yahoo mail with it?
Also it comes with the PC Share Manager, but it is not able to find the Samsung TV and was wondering why and what the purpose is of this software?
Last but not least, I am able to connect my iPhone 3G to the USB port and it detects it, but no media is found. I got the same issue with any other USB drive that I connect...is there a reason for this?