Oil prices prices have a boom and bust history.

Which is one of the advantages of using a renewable resource, it's not subject to the whims of the market.

There is no evidence to believe that wind and alternatives will be cheaper in the next decade or perhaps in this century.  There is no indication at all that coal will be more costly than wind/solar at all.

From the Wikipedia:

Investment capital flowing into renewable energy climbed from $80 billion in 2005 to a record $100 billion in 2006.[14] This level of investment combined with continuing double digit percentage increases each year has moved what once was considered alternative energy to mainstream. Wind was the first to provide 1% of electricity, but solar is not far behind.[15] Some very large corporations such as BP, General Electric, Sharp, and Royal Dutch Shell are investing in the renewable energy sector.[16][17]

Googling wind Kwh per hour cost yielded this:

From 2000 to 2004, wind energy was one of the fastest-growing energy technologies worldwide, growing at a 30% rate to a total installed capacity of more than 46,000 megawatts at the beginning of 2005. The size of the annual worldwide wind energy market is $1.5 billion. The largest share of new wind capacity -- 73% -- was installed in Europe. Spain, where wind power currently provides about 5% of the nation's power, promises to be one of the strongest markets in the next 10 years. Germany has now surpassed the United States, once the world leader, in installed wind energy capacity with more than 16,000 megawatts (MW).

In the United States, wind energy growth slowed during the past several years, a result of uncertainties about deregulation and competition in the electric power industry. Total U.S. installed wind capacity at the end of 2004 was around 6,700 MW, with more than 2,000 MW installed in the last two years. This is enough energy to serve more than 1.6 million average households. Much of the recent growth in the United States was fueled by new State Renewable Portfolio Standards.

Competition in the electric industry means low-cost generation is important. Wind energy, however, offers other competitive advantages: it is clean, renewable, and preferred by some consumers. And as concerns about global climate change grow, wind energy will take a more prominent place among generation technologies. The electric industry remains the largest, single stationary source of air pollution.

Markets for off-grid systems are also strong. More than 2 billion people around the world live without electricity. Small wind turbines, coupled with other technology, such as diesel generators, photovoltaics, and batteries (collectively called hybrid systems), can provide power for remote villages. According to the World Bank, several million households worldwide are able and willing to spend $150 per year for reliable energy.

Switching now because a source of power may become cheaper in the future is a prescription for a lower standard of living for everyone.

Wind energy is one of the most
cost-competitive renewable energy technologies. Thanks to the efforts of the wind industry and the U.S. Department of Energy's (DOE) Wind Energy Program, the cost of electricity from wind has dropped from $0.35 per kilowatt-hour (kWh) in 1980 to less than $0.05 per kWh today at good wind sites. DOE's goal is to improve the technology to further reduce costs to $0.03 per kWh for projects at low wind speed sites and $0.05 per kWh for offshore sites by 2012.