I've been lucky enough to get a loan commitment. What do I do now?

Congratulations! You're one of few. The next step is to negotiate the commitment letter. There was a great article about negotiating loan commitments in the January/February 2010 issue of Business Law Today. The article was titled "Negotiating the Loan Commitment: The Borrower's Perspective" and was authored by John N. Oest. Below are some of the major points made in the article:

Negotiate your important points up front before signing the commitment letter. You will probably not get another opportunity.
Understand that the commitment letter likely contains a number of conditions to the bank's commitment, and few for the borrower. Some commitment letters contain an express agreement by the borrower to borrow the funds.
Negotiate basic financial terms in the commitment letter, including amount of loan, interest rate, maturity date, fees, financial covenants and method of calculation of interest.
Understand at the commitment letter stage how much money will actually be available to you. For example, if your loan is based on "80 percent of Eligible Accounts Receivable" or some similar formulation, you'll need to understand up front what constitutes an Eligible Account Receivable. If you do not, you could end up with less money available to you than you expect.
Work through the prepayment rights and obligations at the commitment letter stage. You may want to prepay the loan, but may find it triggers penalties or yield protection payments . Also, you need to understand when you will be required to repay the loan. Often, an equity raise or a sale of substantial properties outside the ordinary course of business will trigger a prepayment requirement.
Look for a due-on-sale clause. Most mortgages contain these provisions that require repayment of the loan upon sale of the property. These may be subject to limited enforceability in some states.
Change of control provisions prohibit transfers of shares of a privately-owned company if the transfer would result in specified percentages of change of ownership. The borrower should ask for some specific exceptions, including permitting transfers among owners and their affiliates, transfers for estate planning purposes and others.
The commitment letter will generally limit other debt and other liens. You should negotiate to obtain some standard exceptions such as unsecured trade debt, subordinated debt, intercompany debt, purchase money debt and capital leases. You may also want to try to get a general basket for unsecured debt in a maximum amount. With respect to liens, you should negotiate to allow existing liens, liens imposed by operation of law, liens security purchase money debt and other liens. Depending on your company's structure, the lender may require guarantees of the loan. You and the guarantors will need to understand the scope of those guarantees.

The basic point is, don't take the commitment letter lightly. The early stage is when the key terms of the credit are mutually established, so pay attention to the details of the commitment letter and negotiate the issues most important to you at this stage.