Do you want to enlarge the life of a game that you love,or do you just want to create some content yourself and become a proffesional modder,then check out these sites which can offer you modding tools,tips,reviews and generally just a ton of mods you can download

www.moddb.com -offers a lot of tutorials and you can usually join a bunch of modding teams

www.modnmod.com -Has some nice reviews of a lot of popular mods you can get aswell as lots of downloads too