Currently the minimum transaction on Bitcoin is 5430 Satoshi, and what about NXT?
Currently the minimum transaction fee is 1 NXT. There are talks about lowering the 1nxt fee, to increase the usage of certain nxt services like messaging. It wouldn't be ideal to cost 5-10cents every time you sent a message.
Right now the fees are as follows:
All NXT transactions cost 1 NXT
Except for when issuing an Asset, which cost: 1000 NXT - which is about $50 USD which greatly prevents asset spam.