Cite This For Me is an online referencing tool like Neil's Toolbox, but this system lets you reference more than one source at once, then download the whole list into Microsoft Word.
Simply choose which type of text you need to reference (book, journal, website, etc), fill in the online form and the website will do the rest - even organising your Reference List / Bibliography into alphabetical order.
Alternatively, if you are looking for something a little more sophisticated, try a Citation Manager...:
Zotero is a free plug-in for the Firefox web-browser (a standalone program is also available) which will automatically extract the necessary referencing details for online sources and e-journals then export these to Microsoft Word (or Open Office) for you in Harvard format.
Adding Author-Date citations and Reference Lists then just becomes a matter of clicking a button!
The system allows you to import the details for books too, either from the ISBN barcode number on the back cover or simply by finding the title on Amazon; and adding other references manually (such as for print journals) is very easy too.
You can also organise all your sources by adding folders, tags or notes; whilst the online synch-ing option means that you can access your library of resources and references anywhere with an internet connection. Click here to find out more.
More resources to help you with Harvard Referencing are available here.