Microsoft Access is a part of Microsoft Office, if you have Microsoft Word or Microsoft Excel or Microsoft FrontPage, you surely would already have Microsoft Access.
Microsoft Access, by the way, is a database management software. Database is a collection of data, arranged in a manner that suits the need. I'm sure, very sure, that unless you're software developers (programmers) or work in a company you won't likely ever need Access at all.
I recommend you should buy (or better, download off the Internet and search for the crack) Microsoft Office 2003 (which includes Access). Microsoft Office is a set of essential tools for Offices, but also a very useful students especially the Microsoft Word.
Info: Microsoft (http://www.microsoft.com/) offers Microsoft Office 2007 BETA 2 for free (beta is a test software, which is finished but are being tested for leftover bugs and glitches), except handling fee, which is $1.5 for downloading or mailed by DVD for. You can download it here: http://www.microsoft.com/office/preview/beta/overview.mspx
btw, you could actually download Office 2007 for complete free (including no $1.5) from other sources, I recommend from bittorrent.