The code I posted at Graph your Perl inheritance structure will draw an inheritance diagram from an existing Perl program. You should be able to modify it to make UML diagrams pretty easily. But you won't be able to edit them graphically.

But you don't say what UML diagrams you're interested in (there are lots of different kinds). Some possibilities that I can think of for diagramming:

• use the debugger hooks to build a sequence or collaboration diagram
• analyze the @ISA structure for a class diagram like my example does
• analyze your POE structures for a class diagram
• analyze the 'use' and 'require' structures (you can use the debugger hooks here too) for a component diagram