pg-db is a module I put together that adds a bunch of things atop node-postgres:

• Simple interface (ex: db.query(sql, [params], function(err, rows)) or db.queryOne(sql, [params], function(err, row)))
• Named parameter support (ex: ... WHERE foo = :foo instead of ... WHERE foo = $1)
• Transactions (more info below)
• Event hooks (ex: log all SQL that's executed or execute non-transactional hook on commit/rollback)

Transactions are implemented using domains. Database interactions automatically take part in an ongoing transaction so there's no need to manually pass a Client object around. Here's an example: https://github.com/sehrope/node-pg-db-examples/blob/master/src/tx.coffee