not just what they are, for example Lehmqpk is traded on the pink sheet and lehmq is whatever. but what that means.... what effect it has

The Q means its in bankruptcy and the PK means its trading in the pinksheets, which is a quote system for stocks that arent listed on an exchange.

The Q signifies in bankruptcy. Do yourself a favor and stay all the way away from this one. Even if this name comes back later, if you buy shares now they will disolve them and leave you with nothing. (ask the folks at Kmart)

When a corporation is late or stops reporting quarterly income & assets it is removed from the major stock exchange becomes a pink sheet stock.
Also if a corporation becomes too small it can become a pink sheet stock.
The initial listing requirements mandate that a company meet specified minimum thresholds for the number of publicly traded shares, total market value, stock price, & number of shareholders. After a company starts trading, it must continue to meet different standards set by the exchanges. Otherwise, the company can be delisted. These continuing standards usually r less stringent than the initial listing requirements.
http://sec.gov//listing.htm
http://en.wikipedia.org/wiki/Pink_Sheets

Please consult the following link