[Babul]

the image at the top in sa-mp.com? i dont think that the pictures are taken from ingame, coz the view distance would not render los santos when you stand in LV. so i assume its taken in MTA. due to the orange sky doesnt build a linear horizon, i guess it got taken by single screenshots, it would explain the bad quality of the sky. if you record a movie, and turn arond 1 time, then you can work with the (RAW) recorded frames from in the video. (and wont cause the sky changing that fast)
this may help you to get a good result: http://cvlab.epfl.ch/~brown/autostitch/autostitch.html it works MAGIC :P