DV 2009 - Important things you have to follow.

You can enter this programe only through internet via the one and only website, which is run by the USA Govt and will accept entries in the given 60 days period.
No paper postal entry can be submitted.
You must be from an eligible country.
You must fullfil the education and/or Required Work experience.
You must be more than 18 years old.
With the entry You must submit a recent photograph of yourself as required.
If you are married you must include your spouse and your natural and legally adopted children of under 21 years and who are also unmarried.
Eligible spouse too can submit an entry as primary applicant, thus a family can submit two entries.
Visit here everyday to find when the US Govt web site is going to accept the entries.

DV 2009, Participating in this lottery is totally Free. But the selected winners will have to pay for the Diversity processing fee, visa fee and related fees and have to buy their Air Tickets. The US congressionally mandated Diversity Immigrant Visa Program is administered on an annual basis by the Department of State, USA and conducted under the terms of Section 203(c) of the Immigration and Nationality Act (INA). Section 131 of the Immigration Act of 1990 (Pub. L. 101-649) amended INA 203 to provide for a new class of immigrants known as "diversity immigrants" (DV immigrants). The Act makes available 50,000 permanent resident visas each year to persons from countries with low rates of immigration to the United States. The instructions for the DV 2009 Diversity Immigrant Visa Program are also available in PDF Format.

The annual DV program, the applications which are accepted in the year 2007 are for the DV Lottery 2009, makes permanent residence visas available to persons meeting the
simple, but strict, eligibility requirements. Applicants for Diversity Visas are chosen by a computer - generated random lottery drawing. The visas, however, are distributed among six geographic regions with a greater number of visas going to regions with lower rates of immigration, and with no visas going to citizens of countries sending more than 50,000 immigrants to the U.S. in the past five years. Within each region, no one country may receive more than seven percent of the available Diversity Visas in any one year.

Source: Dept of State, USA