I'm just switching from Emacs to IDEA and it would be a great help to me if I could use shortcuts like Ctrl-A for jump-to-line-start. etc. Is this possible?
Go to Settings -> IDE Settings -> Keymap and you will have all the keymappsing.
One of the Keymaps you can select from is Emacs.
A note from a long time Emacs and IDEA user - Emacs bindings in IDEA are simply mission impossible. Arthur is perfectly correct about how to enable them, but they will seriously tamper with your IDEA workflow since they tend to override a lot of default IDEA keybindings and in the end you have to come up with completely custom keymap. This is not a problem the first time - but when you have to work on some coworkers machines, or on other computers it becomes extremely annoying. I used to hold my keymap in Subversion.
So basically don't use the default Emacs keybinding in IDEA - copy the basic setup and extend it personally. The IDEA server might be helpful to keep several computers in sync with the same keybindings.
Also keep in mind that only basic navigational commands are supported in IDEA and some helpful IDEA actions may wind up without keybindings by default so pay extra attention how you configure your IDEA.
For me there is only like place like Emacs - and that's Emacs. I have yet to see some software that provides sensible settings using Emacs keybindings.