The HelloOX method to set Symbian free on new phones with new firmware allows you to install the Symbian modifier ROMPatcher.

Unfortunately ROMPatcher and the Nokia N96 didn't go very well together.

But erkk at the Symbian Freak forum repacked HelloOX with a version of ROMPatcher that works on the N96. This combines well with the installserver patch for ROMPatcher that lets you install unsigned programs without having to deal with the censors at Symbian Signed.

HelloOX 1.03 with ROMPatcher for Nokia N96 at Symbian Freak ( login/signup required)
HelloOX 1.03 with ROMPatcher for Nokia N96 (no need to log in)