Try general search for these items: GIMP (Like Photoshop)
Photoshop 8 or 9 (You just have
to go back on line and reg them)
Registax 5 (or 4) Very Good
Imerge (Makes Mosaics)
Noiseware Community (Noise
Image Grab (Takes a Video or
AVI file and strips it into individ images
Dark Adapted or NightBar. (turns
screen of computor red for night veiwing)
wxAstro &/or Craterlet Image
capture Prog's. (Prefer wxAstro Use
Craterlet just for Moon)
Check these out too : TSOL ( a simple observing log) you will find others there too such as TSOL and OOLog and a Messier Ob's log list..
Virtual Moon. Blink Comparator (Helps find Asteroids) DeepSky Stacker (More complex that REgistax) & Jupiter 2 emph'.
Hope these help you start. StevenA