Part 1:
Unfortunately, Apple doesn't officially support any brand except Wacom for use with Ink. Luckily however, you can force Ink to start and then stay on between reboots. Go to /System -> Library -> Components -> Ink.component -> Contents -> SharedSupport/ and you'll find InkServer.app. Double-click it to start it, and the InkPad should appear on your screen. Once InkPad is open, choose "Open Ink Preferences" and you'll see the Ink prefpane. In the preferences, turn handwriting recognition on. From now on, Ink will appear in System Preferences until you turn handwriting recognition off. Feel free to close the InkPad, you can open it again through the preferences or the menu item without having to dig through /System again.
Part 2:
One of the best apps for using a tablet to draw with is Flash, especially with it's pencil smoothing features. But as luck would have it, use a non-Wacom tablet, and Flash MX crashes as soon as you touch pen to tablet. Not to worry! Those lunatics at Macromedia decided no-one other than Wacom would ever make tablets, so we just have to humour them. Download the Wacom tablet drivers and install them; they don't do anything (they won't even recognise your tablet), but they will stop Flash from crashing and let you use the full feature set (e.g. pressure sensitivity with the brush tool). Enjoy!

