First of all: if you haven't yet memorized the metric system, here is a useful table. (It's a pdf file, so you'll need the Acrobat Reader.)
For those of you who find converting to be a bit confusing, I've written a small spreadsheet that will automatically create practice problems for you. It also allows you to view a step-by-step solution to each practice problem, in order for you to check your work and to decide if you made a mistake and what it was, if so.
Microsoft Office Version
If you must use Microsoft's "Office" program, that version is available here. Note that the free "Microsoft Office Excel Viewer" doesn't actually work - it opens the file, but the numbers won't generate. To use the Microsoft Excel version of the practice problems you'll have to work on a computer that has Microsoft Excel (the full version) installed, and will need to be sure that the Macro security is not set to "high" or "very high." NOTE: In order to run the Excel spreadsheets, you'll need to have the Analysis ToolPak Add-In installed. It's really easy to do. Just open up Excel and go to Tools on the menu bar, and follow: Tools->Add-Ins->Analysis ToolPak (check box). This gives Excel the functionality to create random numbers each time you press F9 and update your spreadsheet.
GOOD NEWS FOR THOSE WHO DO NOT OWN (OR DISLIKE) MICROSOFT OFFICE: Microsoft has competition. There is a completely free, completely functional competitor for Microsoft Office called "OpenOffice.org" which includes a word processor, a presentation program, a mathematical function generator, a vector drawing program, a spreadsheet program (which is the one of interest at the moment!) and a database. For more information, visit http://www.openoffice.org/. I have written a modified version of the practice exercise which is optimized to run on "Calc," the Openoffice.org spreadsheet program. Once you have installed Openoffice.org, you can download the Openoffice version of the practice exercise, here.