For Scrypt try out
https://www.multipool.us/ this is my favorite and they do NOT dump/sell coins for you which is a great thing btw.
For Bitcoin try out
https://bitminter.com/ or other ones already mentioned. It has built in automatic merge mining for Namecoin.
Note both the above are secure sites (much harder to hack) by way of https which is a huge bonus as far as I am concerned!
For CryptoGenicBullion (CGB) (my #1 pick for future success) see no other than my favorite mining pool:
https://www.multipool.us/ http://cryptogenicbullion.org/ For Litecoins (with the most steady production rates that I have found) try out
http://www.wemineltc.com/index For Novacoin try out
https://nvc.khore.org/stats For the newbie and experienced miner alike I believe they will ultimately luv all the above mining sites. And especially mining CryptoGenicBullion (CGB) through the end of this year when the initial max. of 1 million CGB will be met! The race to the finish line of producing 1 million CGB is on... Get your share of CGB or you may really wish you had!
Just be wary of wasting mining energy and time on what may prove to be failed Alt. Coins/Currencies.
Choose wisely (spend time researching).
CLICK the NAME of each currency at this link to do your research at their home sites
http://coinmarketcap.com/ For what Currency is most productive relative to current mining rates see the following sites but beware of dogs (shitcoins):
http://www.coinwarz.com/cryptocurrency = my favorite.
http://coinchoose.com/ http://www.criptovalute.it/profitOther sites worthy of mention:
http://altcoins.com/http://cryptolife.net/ for Scamcoins / Altcoins.
http://cryptometer.org/index.html for historical Blockchain data to determine if listed coins are Premined or Insta-mined.
For Bitcoin & Cryptocoin News:
http://www.thebitcoinchannel.com/http://www.cryptocoinsnews.com/http://www.cryptocurrency.org/http://cryptosource.org/news/http://thegenesisblock.com/http://mining.thegenesisblock.com/ (for ASIC Mining Hardware Specs and Prices)
And importantly:
https://en.bitcoin.it/wiki/Securing_your_walletPlus; Off Topic but Critical:
http://dollarcollapse.com/ This is much more than asked for but surely some great links for newbies and experienced miners alike!
Enjoy.
Caveat emptor - let the buyer beware!