Sierra Wireless Aircard 750 on Tiger 21 Apr, 2008
I had the pleasure of testing out a Sierra Wireless Aircard 750 last month and had to make some tweaks to get it working on OSX 10.4.11. It now responds to AT commands at least but I didn't get a successful connect (perhaps it's not activated).
Be warned the driver doesn't include a top-level folder so create one and extract into it. The original site is xochi.com/aircard.
You may get errors while loading the kernel module. If so, you just need to adjust the ownership to root:wheel (root:admin doesn't count).