incremental backup of postgres database?

Hi!

What would be the best suggestion for incremental backup of a rather large 
database, where the bulk data volume consists of large objects. Since 
backup will be transmitted over a 2 Mbit/s internet line, we need to 
minimize the data flow for each nightly backup. The compressed database 
dump file, when dumped with pg_dump -F c -b, is roughly 2.5 GB, whereas a 
dump without large objects is roughly is only 2% that size. I can live with 
having to transfer the BLOB-less dump every night, but not several 
gigabytes of data...

So, I will either need to find  a way to get the latest data (I have 
timestamps for all LOBS) and somehow get it to a file in a restorable 
format... One simple way would be to select all new blobs into a temp file 
and copy that table to a backup file

or

replicate the database in real time to the backup site, using one of the 
replication projects? How robust are the replication systems today? What 
will happen if the 2Mb/s line fails temporarily?

Perhaps there are other ideas for incremental backup of postgres databases? 
Your input would be much appreciated.

Thanks
Palle