Update: In June 2010, Microsoft released the latest version of their flagship Office suite: Microsoft Office 2010. As a result, Mircosoft is no longer offering the free trial of the older 2007 version as a download. This page still gets visitors from Google, so I assume that students still need to get that 2007 version of Office for computer classes.

Microsoft Office 2007 180-day Trial CD on Amazon

Having done some research, it appears that a Amazon has the free trial CD-ROM from various sellers:

Microsoft Office 2007 180-day trial
and
Microsoft Office 2007 180-day Trial CD

You can also buy the CD-ROM from textbook publisher Prentice Hall here:

Microsoft Office 2007 180-day Trial CD Spring 2011, 9th Edition

If you want to try the latest version of Microsoft Office, you can follow the links in the original article is below:

If you’re a student (or teacher, or parent of a student) and you’re shopping for software like Microsoft Office 2007, you can save money with an academic discount, from a source like journeyed.com.

But maybe you don’t even need to spend anything at all …at least not yet!

Microsoft offers a free 60-day trial version of Office 2007 Professional Edition which you can download at http://www.trymicrosoftoffice.com/

Update, June 2010:
Since the release of the new of Microsoft  Office, the link above will enable you to try the new version: Office 2010.
The information below about downloading and activating the free trial software is still valid for the latest version of Office.

If you only need Microsoft Office for a limited time—maybe for a class you are taking, or until you save the money to buy the full product—you can download it and try it free for 60 days.

Here’s how the free download process works:

Go to trymicrosoftoffice.com and click on the download link

You’ll need to sign in with a Windows Live ID or Microsoft Passport account to download the software.

If you have a Hotmail email account, or a MSN email account, you can sign in with those credentials. Otherwise you can create a new account on the spot.

When you sign in, you’ll be creating an account with Microsoft Office 2007 Trial program to receive a product key for the trial version of Office 2007 Professional. You will also receive a series of emails on information about the software.

After sign-in you’ll be taken to a page where you’ll find a personal Microsoft Office Product Key. Save that key because you’ll need it to install your software. You also find that button that you will click to initiate the download.

This is obviously going to be a huge download, so you’ll need to have a high speed Internet connection (like DSL or cable Internet). Also, once you install your download software, you’ll need to activate it to begin your 60-day trial, and this also requires an Internet connection.

Activating the product begins the 60-day trial period. As you near the end of that trial phase, the software will alert you to the fact that it will expire soon, and encourage you to purchase or “convert” the software to the paid version of the software.

Remember that students and faculty can obtain this software and academic discount, so rather than paying full price during the “conversion” process, you may want to buy the student version online from a source like journeyed.com (for as little as US $79.98).

Here’s a few facts that you might need to know about the trial version of Office 2007 Professional:

If you’re using Outlook 2003 (from the previous version of Office) you should be aware that two versions of Outlook cannot be installed on a computer at the same time. When you install the trial version, Outlook 2007 is not automatically installed Outlook 2003 already resides on the computer. This will actually make your life easier if you decide to uninstall the trial version of Office 2007 when it expires after 60 days.

After 60 days, your trial software will no longer be fully functional. It will operate only in a read-only mode that will allow you to view your documents but not change them. Any documents you’ve created will not expire; they’ll be just fine and you can open and edit them in any fully functional version of Office 2007.

If you’ve already used a trial version of one of the office 2007 products, you’ll probably find that you will not be able to activate and use the 60-day trial version of Office 2007 because your trial period has already expired.