Thanks for the kind words... most of what I do comes from others on this forum, and I have a lot of learning still to go.
To get the pictures at the baseball game, I upped the ISO to 640 since it was a little rainy and not very bright light. This allowed two things: First, a higher shutter speed to keep motion blur down at 200 to 300mm. Secondly, it allowed me to stop it down between f/6.3 and f/9; it appears the lens performs better stopped down (f/8 and above?, hard to say).
The duck shot was on my first walk-about with the lens. It was a very bright winter day, the the 70-300 seems to like a lot of light.
As for post-processing, I shoot everything in RAW and follow a workflow from "PSCS2 Workflow" by Tim Grey. I've only read a couple chapters, but it's helped in many subtle ways. All the baseball pictures have been post-processed for white ballance, exposure, shadows, etc., etc. down to sharpening, so they're definitely not "straight-out-of-the-camera"!
Here are the rest of the baseball pictures with EXIF data:
http://www.pbase.com/purkers/osubaseball
Hope this helps!