how do I move a project from one account to another.

On the project settings page, under the General section, the current account for the project is listed. Account Owners and people who are authorized to create projects can migrate projects between accounts they control.

In your specific case, identify a user account that is one of your account owners. You can see the list of account owners by clicking the Manage link on the My Accounts page. Once you have identified an account owner on your account, you need to get the consultants to temporarily grant that user project creation rights in their account. They can do so on the Manage Account screen for their account.

Once you have an owner on your account empowered to create projects in the consulting firm's account, that user should see the account name on the project settings page not as plain text but as a link. Click (Change) next to the link and change the account from the consulting firm's account to your account, and then click Save.

I know it's a bit convoluted with the permissions and whatnot, and as soon as you've migrated the project the consulting firm can remove project creation privileges from your account owner. Let us know if you have any problems.