Do you usually give your clients invoices? If so, would it be possible for me to see a sample? I'm not quite sure how exactly an invoice should look like and what content it should contain, so a sample one would be helpful. Thanks in advance.

adrienne -- do yourself a favor and sign-up with an account at www.sidejobtrack.com.

Not only is the default template nice -- you can pick from other invoice templates that others have created and shared. I won't bother linking to an example of my freelance invoice as it is just a personal revision to the default template.

Beyond invoicing, it proves as a great mechanism for tracking revenue, clients content information and payment due dates. If you are using nothing right now, this will change your life.

I use blinksale (http://blinksale.com) which has a free invoicing tool for 3 invoices. It is also tied up with paypal, so if anyone pays you through paypal the reference number is automatically noted and the invoice is marked as paid.

Although Blinksale and Sidejobtrack are undoubtedly great tools (I've used both), I would always recommend sending a .PDF formatted invoice. An invoice is part of your company, it should reflect your brand. Not just someone elses design or layout with your logo slapped at the top.

Maybe I'll get slated for this but HTML for invoicing just seems wrong to me.

I created my invoice template using Open Office which is an Open Source spreadsheet application. It allows you to export the document as PDF for emailing to the client.