No Oracle Database 11g for Mac!

While Linux is a perfectly cromulent option, I have no idea how to install it, use it or work within it, and I feel like that would ramp the difficulty level way up. I need it to be on familiar ground.

Honestly, if you're going to be working with computers for a living, you need to learn linux eventually, especially with anything DB related. You'll spend 90% of your time in the command line anyway. Most vm based linux installations are basically idiot-proof.

[Okay, folks, OP has heard the Linux recommendation now, so let's get back to the original question, please.]

Does it need to be Windows? Perhaps run https://www.virtualbox.org and install some flavor of Linux (download and install an ISO of, say, http://www.ubuntu.com/download/server) to run Oracle Database 11g for Linux.

Maybe you can buy a Windows Product Key from your campus bookstore (unless you already have one), and you can http://answers.microsoft.com/en-us/windows/forum/windows_7-windows_install/where-can-i-download-windows-7-iso-i-have-a/7d964b05-2be9-4800-bc7f-3ca30356fc3d. Once you have the ISO, you can http://its.yale.edu/how-to/installing-windows-macintosh-computer-using-virtual-box (skip step 2, since you would have an ISO).

You can download a Virtual Box image with Linux and Oracle preinstalled/configured from https://tech.lds.org/wiki/Oracle_VM. It works great on my mac and was the best option for me. You can then install SQL Developer on your macbook and connect to the server on the Virtualbox. So you don't have to work in Linux all the time, it's just the server running on a Linux VM.

Seconding what empath said. Also, just about anything you learn about the command-line in Linux will work on the Mac. Learning your way around the UNIX command line is a must for any developer, especially one working on the Mac.

Would the Vista machine work at least well enough to get Oracle up and running on it? Both http://www.vmware.com/products/fusion/ and http://www.parallels.com/products/transporter/ have the capability to do a physical-to-virtual conversion - you put a helper app sort of deal on the Windows system and it does whatever magic is required to convert it into a VM that you can then run on your Mac. (Fusion comes with it but Parallels Desktop does not; there's a separate Transporter app that does it there.) Alternatively, if you've got an Internet connection that thing can sit on, you can also do something like https://secure.logmein.com/products/free/ or something similar to use the machine remotely. I've used the free tier of LogMeIn and it works pretty well, even over slower connections (which you probably have, at least for upload, for a home Internet connection). It'll also allow you to power the system on too but you should test that before relying on it; I don't know how that actually works. Another option: Amazon RDS is essentially EC2 for databases, and http://aws.amazon.com/rds/oracle/ref=amb_link_380676922_2/. No express edition, though, just standard (and enterprise if you have a license). There's a free tier for that too so you could potentially look at that as well? Yet another option (definitely not free but not horribly expensive): get a Windows VPS from somewhere. This can be Amazon EC2 as well if you want, though it might be kinda pricy to spin up one that'd be usable for Oracle maybe. I have a Windows VPS through http://www.softsyshosting.com/windows-vps.aspx and it works pretty well. I can remote desktop into it and all that. Not free, of course, but it'd run you about $60 for the Eco2 one there through the course. There's a bunch of VPS providers out there too so you might be able to find one cheaper (especially if you don't care about the data on it or anything).

I would recommend using one of the Linux prepackaged VMs, but if you must use windows, 180-day trial ISO images are available, and you could create a VM with it. Here's one for Server 2008 R2: http://www.microsoft.com/en-us/download/details.aspx?id=11093