Morgaine is right there is no easy way to do a cash flow.
What I look for beside the basic text book adjustments (e.g. Depreciation) is anything on the balance sheet and income statement that might be a non-cash item such as amortization of deferred finance costs or items in Other Comprehensive Income.
Also, you'll need to get the amount in PP&E that actually was not paid as cash but is still in AP or accrued expenses. It is not just the change in PP&E if it was not really paid for.
And I just mentioned a few of categories. You really need to know a lot about the company to do a "real life" cash flow. It takes understanding each line item in the BS and IS and many discussions with other areas of the company. If this is not a school project, I would recommend someone training you or at least providing you with contacts within the organization.