Let's assume the lump sum does come in over $6.4 million (for lottery winners, it can sometimes come in a little lower than what the lottery tells you). Without knowing much else about your situation, I would pay off the cards, the student loan, and the mortgage, even with the good rate. (If you have car loans, pay those off too.)
That leaves you with around $6.1 million. Take $100,000 of that and set it aside, especially if you want to start your own company instead of working for the man. That leaves you with about $6 million to invest.
I agree that you probably don't need an attorney right now ... estate tax minimums have just gone up, so there may not be a need (yet) to set up things like family limited partnerships and other legal vehicles to minimize taxes. You will need an accountant and a financial planner for sure, however.
Simple math on the $6 million: Assuming a portfolio that is half equities and half fixed income, you can certainly approach $200,000 a year of mostly tax-free income. Some small % of the bonds should be higher-yielding BB taxable bonds, but the vast majority should be A and AA munis with a short duration (longer duration portfolios will get whipsawed as rates rise). On the equity side, you should strive to keep it relatively safe - and it is pretty easy these days to maintain an average dividend yield of over 1.5% while keeping a decent growth component. Dividend tax rates are very low until at least 2013, when the government will next address the issue. That should get you close to $200K a year without much of a tax bill along the way, and with relatively low risk.
On the jobs - I would stay in them for a little while longer even though you hate them. First, you don't actually have the money yet, and second, if you have an entrepreneurial mindset, it is better to come up with ideas and lay the groundwork while still on someone else's payroll. (Also think through your benefits). Give the jobs at least three months after the money hits your account at least.
Disclosure - I am president of a planning/asset management firm based in Florida with several excellent CFPs on staff. Please let me know if you need more help.