What are some great sites that offer content and mods for Fallout NV/3 and the TES series ?
The only I know of is f3Underground (VGU), Nexus (obviously) and ModGames.

Also youtubing something very specific could help me find a mod uploaded on megaupload or something else.

Well the others sites I use are:
modsreloaded.com
moddb.com

Both have a couple of intresting mods for F3/FNV and TES. But it is more like a database then a forum or something.

The Engineering Guild has a few really good mods for Oblivion, Skyrim, Fallout 3, and Fallout New Vegas.
TesAlliance has a lot of mods for Oblivion and Skyrim, as well as a few mods for Morrowind and the Fallout games.
The Assimilation Lab has a number of big mods for The Elder Scrolls games they are working on, such as the Black Marsh project for Oblivion they've been working on, which is now in Alpha.
Great House Fliggerty is mainly focused on Morrowind, but it has a few Obivion and Fallout 3 mods as well. It is one of the two best places to find Morrowind mods though.
Morrowind Modding History is the other best place to find Morrowind mods, especially older mods which can no longer be found elsewhere.
Have you ever wanted to play Morrowind and Oblivion in the same game? Or Skyrim, Morrowind, and Oblivion all in the same game? Then look no further than TESRenewal, where you can get Morroblivion, Skywind, and Skyblivion. Both Skywind, and especially Skyblivion are still in early development, but Morroblivion is mostly completed.
Tamriel Rebuilt is probably the biggest mod project for Morrowind. Working to add the rest of the province to the game. They have a lot to do, but what they have added already is massive.
Unfortunately I cannot post links. But they should be easy to find via searching for their names. If not don't hesitate to ask for more help.

I wouldn't recommend The Engineering Guild because Giskards mod have a tendency to not play well with others. They tend to be filled with wild edits and identical to masters because he refuses to use any 3rd party program because he claims they are all inherently broken. He has gotten himself banned from pretty much all of the relevant modding forums due in part to arguments over such (against essentially the rest of the modding community) and general douchebaggery.

Most of Big projects are dying, unfortunatelly =(

Except TesRenewal, I beleive. They`re working quite fast, guys upload updates every now and then.

These all look neat gonna have to check some of them out

Visious wrote:

Most of Big projects are dying, unfortunatelly =(

Except TesRenewal, I beleive. They`re working quite fast, guys upload updates every now and then.

The big projects pretty much always die off though. Imagining something is far different than getting it implemented. I know I have started a house about 5 times now and always end up hitting a wall and erasing everything.

Even then, the "bigger" projects I have been looking forward to are still in progress, namely Luftahraan and Ashes of Eris.

There's also LoversLab to which I'm a active member, if you can get past the more adult-orientation of the site, there's some really good stuff there.
And maybe an ad-blocker to get rid of those adult web ads.

LaEspada wrote:

There's also LoversLab to which I'm a active member, if you can get past the more adult-orientation of the site, there's some really good stuff there.
And maybe an ad-blocker to get rid of those adult web ads.

Whats there? FNV plugins or for all Bethesda games?

It has mods for Fallout 3 & New Vegas, Skyrim, and Oblivion.

http://modtype.doorblog.jp/ some of the mods are hosted on other sites
http://mod.dysintropi.me/ mods made bye halo(i assume thats her/his name)
http://dragonporn.ldblog.jp/ i dont know if this counts because its more or less a showcase site but it does have some mods that cant be found else where
http://haishao.blogspot.jp/ same as the one before although it seems that most of these modders have disappeared off the rader drawing this conclusion for the lack of updates