Swap is like virtual memory. In Windows, a page file located on your primary hard drive serves this purpose, but in Linux, a dedicated partition is reserved for "virtual memory" and is called the Swap partition.
Ext3 is a type of filesystem. It is Linux's equivalent of NTFS, but it doesn't require defragmentation. You can read ext3fs formatted partitions or drives using
Ext2 IFS For Windows for Windows XP.
On Linux, your hard drive isn't "located" anywhere in particular. Unlike Windows, where symbolic links to drives are located under a central "My Computer" under a Desktop (which is a combination of My Computer, My Network Places, and a folder on your hard drive), Linux has what is called the Root Directory, or /. Your hard drive's ext3fs partition's root folder is /, with subfolders for both items on the ext3fs partition and those from other drives. Linux uses "mounting" to attach locations off of the main partition to the filesystem. Ubuntu mounts other devices for you, and locates them under /media. A CD-ROM, for example, may show up under /media/cdrom. If the CD is named "My Picture CD", Ubuntu may mount it as /media/cdrom, but it will put an icon on the Desktop labeled "My Picture CD", which is a temporary "shortcut" (using Windows analogies) to the /media/cdrom folder. You can mount other partitions as well, such as FAT, FAT32, NTFS, ext2, and others. I prefer to mount everything under /media, to keep the system uniform (mount Windows partition as /media/windows, storage drive as /media/storage, etc).
