Here's whatsnew:

"Support for execution breakpoints has been readded, along with brand new support for memory read/write breakpoints.
Opcode breakpoints (i.e. break when a specific opcode is encountered) and interrupt breakpoints (NMI and IRQ, as well as BRK, which is logically equivalent to opcode 00) are planned - they will be implemented at a later date.
Note that this new breakpoint support has not been fully tested - if you encounter any problems, please contact me either via e-mail (address here) or on IRC (irc.freenode.net #nesvideos)."

Get it here:
http://www.qmtpro.com/~nes/nintendulator/

-Trebor