Memory leaks?

Ok, I have an application which uses posgresql.

While testing the system (inserting many records into
a database (with large objects) the system ran out of memory
(the system has 64M RAM + 128M SWAP). Sorting the processes
according to memory usage showed me a postgres process with 160M of 
memory (+-80%) used.

Any tips for helping me find out what's going on here? How do you guys
check for leaks?

Thanks 
  Maurice