Reading Windows-disks on a Mac?

If your external is FAT32, you should be able to read from it and write to it in OS X without having to take any special steps.

If your external is formatted NTFS, any version of OS X past 10.4 (Tiger) should be able to read from the disk by default, but if you want to write to an NTFS disk, you will have to install special software or possibly go through some fairly complicated steps to enable write support in Snow Leopard. Be careful, though - I've heard of a few bad experiences with writing to an NTFS disk in anything other than Windows.

FMI, try here, here, and here.

So in summary, you should be able to read a Windows disk just fine and by default with any version of OS X from 10.4 (Tiger) all the way up through the current 10.6 (Snow Leopard).

 

FAT32 (File Allocation Table)

• Read/Write FAT32 from both native Windows and native Mac OS X.
• Maximum file size: 4GB.
• Maximum volume size: 2TB

NTFS (Windows NT File System)

• Read/Write NTFS from native Windows.
• Read only NTFS from native Mac OS X
• To Read/Write/Format NTFS from Mac OS X: Install NTFS-3G for Mac OS X (free)
• Some have reported problems using Tuxera (approx 33USD).
• Native NTFS support can be enabled in Snow Leopard, but is not advisable, due to instability.
• Maximum file size: 16 TB
• Maximum volume size: 256TB

HFS+ (Hierarchical File System, a.k.a. Mac OS Extended)

• Read/Write HFS+ from native Mac OS X
• Required for Time Machine or Carbon Copy Cloner backups of Mac internal hard drive.
• To Read/Write HFS+ from Windows, Install MacDrive
• To Read HFS+ (but not Write) from Windows, Install HFSExplorer
• Maximum file size: 8EiB
• Maximum volume size: 8EiB