FOSS web-based accounting?

[DraconianTimes]

I run a small information security consulting firm in the UK (three people now, plus office admin person to join early next year), and am looking for a web-based accounts system which I can access when on the road. The accounting system I have now is extremely basic and is already a massive burden on my time.

We have an OpenBSD server which has most of the corporate records (HR etc) plus client project work. We run OpenBSD's base Apache, PHP 5.2.6 (with Suhosin) and PostgreSQL. We already use WebCalendar and a couple of other small apps on there. I already do manual invoicing with MSExcel and am looking to move that to BambooInvoice in the next couple of months.

Does anyone have any experience with any of the free, open-source, web-based accounting apps (stuff like LedgerSMB)? Ideally I'd like something that will work with PostgreSQL. Whatever we use will have to be double entry, support security for multiple users, in English and able to cope with working in GBP currency. I'd love to have an employee expenses module which I could enable and allow people to file their expenses directly on the system.

Would appreciate any advice, anecdotes or caveats from those of you have have knowledge or hands-on experience of any the various projects out there.

Cheers...

Nick