Id like to know if there is amining pool that allow us to mine Bitcoins, Namecoins and Litecoins at the same time.
I kow there is some that allow us to mine Bitcoins and Litecoins but I couldnt find one to mine those three.
Bitcoins and Namecoins can be mined at the same time, because the underlying algorithm is the same. But you can not mine Litecoin and Bitcoin at the same time without the loss of hashes/sec, because it uses different crypto algorithms. Therefore I highly doubt that there is something like you have claimed in your question.
BTW, there is a pool where you can mine a lot of different cryptocurrencies (but separately). https://coinotron.com/
another site like the one above - https://www.multipool.us/ - i guess it has a algorithm that changes the coin you are mining depending on the profitability on BTC - i read it was pretty good. I JUST joined/found it like 3 days ago lol have yet to start mining
As mentioned before, the loss in hashes means that bitcoins can't be mined efficiently on the same hardware as litecoins.
I've been using http://cex.io/ which mines a number of other coins at the same time, such as namecoin and devcoin. It's backbone is ghash.io, which is the largest mining pool out there.
Depending on how much gigahashes you buy, you could see a return pretty quick. I pondered investing in hardware, but it seems somewhat expensive now.