Hi Justin,
My apple keyboard does not have an insert or alt key.
My powerbook keyboard has the Alt key, two to the left
of the space bar. It's also marked "option". For laptops,
you can adjust the keyboard layout from "desktop" to
"laptop". See the first option on the General pane in the
Orca Preferences dialog. This then uses the Caps Lock
key instead of the Insert key for chorded commands. In
other words, Insert+Enter becomes Caps_Lock+Enter.
There is also a keyboard mapping pane in the Preferences
dialog. From there you can adjust any key bindings you
want to.