Post a photo? Well I think it would be beneficial if you used a computer, but as long as you have fast internet, and a browser on your iPodTouch, I dont think your going to have a single problem in your way -
1) I suggest you use photobucket, so download the photobucket app for iPhone on your iPodTouch.
2) Take a photo and make sure its saved in your photos or photostream.
3) if your planning on cropping the picture, make sure you use Aviary or Snapbucket. I use those two to edit my photos (for my log). If you crop it when you use the Photos app, when you upload the photo, it will remain the way when you first took the photo, not the cropped one.
4) Click on the album and you'll see an arrow going up, click on that and click on the photos you want to upload.
5) After uploading, go on your browser (Safari) and go on photobucket on your account.
6) Click on the IMG code and copy it all. Then open up TamaTalk.
7) For example, when I use an IMG code, its for my log. Paste the IMG code to wherever you posted.
There! Your photo is now on a TT post! Enjoy.