Here are some resources you may find useful to help manage business finances :
Receipt Bank
A very useful app that allows you to photograph all of your receipts using your phone and have them uploaded to a server where they are remotely analysed and the data is then inserted to a file that you can review and send to your book keeper . This app has transformed my life!!
Sage Accounts
Accounting software - very popular with accountants and book keepers in the UK
XERO
Online accounting software, I've switched to this for my Aussie business and it's incredible. Very easy to see your P&L at a moments notice plus what cash is available including who owes you money and what your current liabilities are. www.xero.com
Kashflow
Another accounting software solution
Paypal
A very popular method of accepting payment if you do not have a credit card merchant account.
XE.com
This gives live foreign exchange rates and is a useful reference when working with international clients.