I will speak from lots of experience being a developer in this space both 
professionally and in free software.

> Two come to mind:
> GNUCash

GNUCash is not for business accounting.  Further more it is local file 
database (not good for business computing), yes I realize they have a 
Postgres version, but its far from stable.

They are working on some small business features but will be more on par 
with Quickbooks(which IMHO is a horrible business accounting package for 
many reasons) than a PeachTree

> Sql Ledger

SQL Ledger showed lots of promise in many ways until you look at its code 
and guts, last I checked you couldnt even reconcile bank accounts.  If you 
are willing to go web accounting.  NOLA from Noguska is much cleaner.

> and perhaps GNUEnterpise > 

I think (biased) that we have the best promise in that we are a Framework 
much like SAP which offers true flexibility, but we dont have a shrink 
wrap accounting pak as of today

Compiere is another nice package, that is polished but currently requires 
an Oracle database (pricey) and is under a weak copyleft license (MPL)


 > Personally, I am begining to take a look 
at Sql Ledger > (www.sql-ledger.org), problem is I'm an ole MySQL guy and
> need to learn more 'bout PostgreSQL

MySQL is not suited for business accounting in any way shape or form for 
many reasons (its a great database for many things, but this aint one of 
them)  I strongly suggest you look at NOLA and give it an evaluation along 
with SQLLedger before making the jump, you will find it worth your time.

Derek Neighbors
GNU Enterprise
http://www.gnuenterprise.org
derek@gnue.org