VirtualBox provides an alternative to VMware for creating and using Linux virtual machines under Windows. VirtualBox is available for free from Oracle. http://www.virtualbox.org/ should get you to it. If not, an internet search (Google, Yahoo, etc.) for VirtualBox should help locate the most up to date location for downloading.
The fastest way to get Xastir up and running is to use a Linux virtual machine with Xastir pre-installed.
There is a virtual machine (VM) for VirtualBox with Xastir pre-installed that can be downloaded via link below. This VM was created in January 2012 using Debian 6 (Squeeze). The XFCE desktop is installed, which is lighter weight than the default gnome desktop.
Download a Pre-built Virtual Machine
Note: the default user which logs in automatically is "user" with a password of "linux", and the root password is "xastir".
The virtual machine is a very large file and has been compressed with 7zip, which provides significantly better compression than most other formats. 7zip is a free download at http://www.7-zip.org/ The files can also be decompressed by Izarc, which is a free download as well via http://www.izarc.org.
The VM has "Linux Additions" installed, which allows the user to change the Xastir/Linux window to virtually any size and shape within the host OS by simply clicking and dragging the sides or corners of the window.