All you gotta do is download them. Unzip them to your Mods folder. For vista its here:  C:\Users\'YourUsername"\AppData\Local\Ironclad Games\Sins of a Solar Empire\Mods

Then Start up the game. Under the Settings tab, there is another tab called Mods. Just click on that and it will bring up the mods you have put into your mods folder. Select the mod you want to enable and then click enable mod.

Just like that your mod is ready to go.

Hey i have vista .... but i tried following that thing but i dont have appdata in my users???? or ironclad folder... i have stardock which has sins in it but when i go into sins of a solar empire.... there is no mod file. Help?

ok now after i did that i put the mod into that folder and when i go to open mods up in the game there is nothing there..... do i have to open the file with like notepad or something like that???