Trading penny stocks can get very tricky. When trading an Over The Counter Bulletin Board (OTCBB) penny stock you can dig through their filings with the SEC and you can read about how well a company is doing, their future plans, and their share structure. Certain companies work very hard to hide dilution of their shares. If you read the filings you should be able to spot any areas of concern and focus on them. If the share structure and possible dilution raises concernce, then you will call the companies transfer agent (listed at the end of filings and press releases) for an update on current operating and authorised shares. Compare the TA's number with the number from the latest filing and you'll have your answer.
This becomes even harder when dealing with Pink Sheet stocks. Unlike OTCBB, Pink Sheets do not have to file with the SEC. They do have a transfer agent that you can call to find out current share structure. They also have a state of incorporation. These companies usually must file within their state the status of the company as well as any major changes. Each state has different rules and some states do better than others in allowing traders to access this information. One place to start is the Secretary of State office from the state the company is incorporated in.