Alliance are a serie of different mods. On the Star Wars GC, you can play the civil war Empire vs Rebel era + Black Sun and soon the Republic and CIS.
This is the Warb_Null Pellaeon Star Destroyer with the texture made by Nawrocki. You can find more about the Legacy era at my site. Firefoxccmods.com
You can probably find more about the Legacy era in the Star Wars wiki:
www.starwars.wikia.com/
The best are the original sources and I have all them.