Pearl's pitch is appealing. Integrate all your web services into one clean package. Let pearl handle CRM, accounting, billing, etc, etc. Feels a bit out of date, trying to be all things to all people. Interesting nonetheless.
CurdBee is an online billing application similar to Freshbooks that supports multiple currencies.
Mint is an auto-book keeping service. Give it your (US only) account nos, etc and it will track all your income and expenditure. Nice.
FreshBooks is an online time tracking / invoicing system. It will generate invoices, accept payments via PayPal / Authorize.net / etc. It sends reminder emails and so on. Packages from $14 to $150 per month.