HP shares plummeted today to its lowest level in six years. At the time of this writing, HP’s shares are down 20.23%. Its shares had fallen as low as 23%. Shaky confidence in HP is directly related to yesterday’s flurry of huge announcements involving HP’s decisions to discontinue webOS hardware and possibly separating or spinning off its personal systems group. This process is expected to take between 12-18 months.

Sources have revealed to the Wall Street Journal that Yahoo! will announce layoffs when they reveal their quarterly earnings tomorrow. The exact number of jobs affected isn’t know but is estimated to be at least 1,000. The move isn’t much of a surprise, however. Last month they hired a consulting firm to help them streamline their operations.

The company, which once boasted the top search engine on the net, has been struggling as of late. Its shares have fallen 32% over the past month, its deal with Google was put on hold due to an FTC investigation, and earlier this year they rejected a takeover bid by Microsoft. Shares entered the week at $12.90 after hitting a 5-year low of $11.37 last week. Microsoft takeover bid was for $33 a share.

Yesterday’s stock tumble has hit tech businesses hard. Nasdaq, which is primarily tech businesses, fell nearly 200 points, and several big tech businesses saw similar drops. Apple fell 18%, AMD nearly 17%, and Intel over 10%. Similarly, Google saw its stock fall over $50 to $381 a share. That’s nearly a 12% drop.

The nightmare on Wall Street may become one for mobile phone makers and providers as well. The financial markets have long provided them with their most profitable customers, but with over 12,000 workers already out of a job and the possibility of tens of thousands more joining them, tough times could be on the horizon. Experts say RIM, the makers of the ultra popular Blackberry, could be especially hard hit. Palm, HTC and HP also stand to be affected.

Demand is already slowing in the U.S. due to the credit crunch and poor housing market. Cell providers have tried to compensate by offering deeper subsidies on their high end handsets, but if predictions come true, it may not be enough. RIM sold nearly 6 million Blackberries last quarter and is preparing to roll out their much anticipated Blackberry Bold, and that seems to have RIM feeling confident they can ride out the storm.