BVSTools has released GreenTools for PayPal (G4PP) v1.00 and now v2.00.  

G4PP v1.00 introduced a set of functions that allow you to create and send an invoice using PayPal's RESTful web apis.

G4PP v2.00 added a bunch more functions including marking an invoice paid, marking an invoice as refunded, cancelling an invoice and updating an invoice.

You can find more information at www.bvstools.com/g4pp.html or in the G4PP docs at http://docs.bvstools.com.  

Additional Information:

• Creating Your First GreenTools for PayPal (G4PP) Invoicing Application Using G4PPINV Addon
• How BVSTools Uses GreenTools for PayPal (G4PP)
• GreenTools for PayPal v3.00 Released - New Features Include Issuing Refunds and Retrieving Account Balance
• GreenTools for PayPal v3.10 Released - Retrieve Invoice Status added to G4PPINV