RPGDot.com is an excellent source of RPG news, reviews and forum discussion. Subsections of forums include BG series, Morrowind, Gothic, Neverwinter Nights and other RPGs such as Vampire: The Masquerade. RPGPlanet also provides game specific sites.
Baldur's Gate mods (including Tutu to run BG1 in BG2) are at Pocket Plane Group
Gothic 1 & 2:RPGdot's Gothic page
Elder Scrolls site & main forum
Mod sites include: Mythic Mods, including Telesphoro's List o' Mods, TheLys' Mods and Petrell's MW links.
Neverwinter Nights: Bioware site and recommended mod list on OO. Neverwinter Vault also has tons of content.