Here is a list of useful microcap and penny stock investor links:

PinkSheets.com – Pink OTC Markets provides the electronic trading platform for U.S. broker-dealers to make markets and provide best execution in OTC traded securities. Active OTC market makers and agency traders utilize our efficient, state-of-the-art, low-cost quotation and trade messaging services to trade over $160 billion in OTCQX, OTCBB, and Pink Sheets securities annually.

OTCBB.com – OTCBB was established to provide transparency and an electronic trading system for the OTC equities market in 1997. OTCBB provides access to more than 3,300 fully reporting securities and includes more than 230 participating Market Makers. The system electronically transmits real-time quote, price and volume information in domestic securities, foreign securities and ADRs. As of October, 2008, trades in all OTCBB securities must be reported within 90 seconds to the system.

MicrocapMarkets.com – is microcap research site for access to full intraday coverage of the Microcap and Nanocap markets. This Institutional-grade site delivers the full gamut of market data, news, regulatory filings and analytics which occurs daily on the 3 main U.S microcap markets: OTC Bulletin Board, Pink Sheets and Nasdaq<$5.

Investorshub.com – One of the best Microcap Message Boards around.