Level 0
We're not involved at all, but we'll announce your event if you ask.
Level 1
We will provide a planning wiki and point you at the Act developers for Act hosting. You can use our event insurance, as long as we know what activities you have planned for your workshop. By accepting this insurance, you agree that your event is a "TPF event" and is being held under the auspices of TPF. This means you keep us in informed of planned activities and we have veto power over anything that might be an insurance risk.
Level 2
Same as Level 1, plus at this level we handle income and expenses, but we don't cover cost overruns. We can take sponsorship checks, making sponsorship tax-deductible in the US. We will also pay expenses based on your current sponsorship level plus a "conservative" estimate of registration.
For TPF to provide this level of support, we'd like to see a basic plan for your workshop which includes a budget summary.
Level 3
Same as Level 2, plus we agree to be responsible for cost overruns. For us to provide this level of support, we want to see a detailed budget, and you have to keep us notified of any significant budget changes as your planning progresses. We'll also expect proceeds, after expenses, to be donated to TPF. This what we do for a YAPC::NA.
This Sample Workshop Plan is an example of what we'd like to see, including a budget.