There are a few new cheap and sometimes FREE accounting and time management tools that are part of the Web 2.0 explosion. You may want to incorporate these to help you manage your business.
Blinksale is great for quick invoicing. I have used it to send invoices to my bookkeeping clients and it faciliates PayPal payments. The only downside is that you can only send three invoices a month for the free version. If you like it, I suggest upgrading to the next level which is only $12/month.
Freshbooks.com offers a similar service but it is not as efficient. More detail for clients has to entered, but they do offer to send in the mail an actual hard copy of the invoice.
MyIntervals is a timetracking application that is great for project management.
Wesabe is more for personal finance but since many of my clients are micro-businesses, it’s a definitely worth a look. I heard that people use Wesabe to see what checks have cleared and what the current balances are for her credit cards.