Intalio makes Open Source Business Process Management (BPM is Business Performance Management, adding an S you get a completely different product). It seems that OS community lacks only some OLAP-server with breakback(write-back, back-solve, call whether you like) to get the planning\budgeting system. Mondrian cannot do that, as far as I know.
In analogue with Ms Performance Point solution, by components (just an example):
| Component | Ms | Open Source Analogue |
| Reporting | Proclarity | Pentaho (there’s a lot more, I know) |
| OLAP Analysis | MS AS | Mondrian(I don’t think Palo is ready for multi-user eviroments) |
| Workflow | BizTalk | Intalio |
| ETL | SSAS | Kettle |
| BreakBack Calculation | WriteBack in MS AS | ??? |
| Database | MS Sql Server | Mysql |
| OS | Windows | Linux |
Just a sketch, of course.