Help needed with Rx & Tx pins

hello...i am complete noob to the Arduino platform and to Mico controllers in general....but have been a elec. enthusiast for a long time....recently bought an Arduino Duemilanove and have been playing around with it a lot....decieded to make a 4x4x4 led cube without using shift registers or demux for the time being and will then move on to a larger version.....my question is this.....all the 'truables that i found for this use 20 pins on the arduino which i understand...but in places i read that pins 0 and 1 (Rx and Tx) shld not be used...especially the direction of the Rx pin shld not be flipped....i am especially interested in understanding this from the perspective of direct port handling which would allow me to simultaneously switch states of multiple pins (i understand that i can light upto 8 leds at the same time).......if i flip the direction of the Rx pin would the board basically stop hooking up to my system....or can i still connect the board and sacrifice only the serial connections (debugging etc.)......would much appreciate any help and ideas.....thanks nitin.....

If you don't use Serial AT ALL, you can do what you want with pins 0 and 1.

thanks paul....so that means that i can use those two pins for now and still upload sketches right? also as and when i need the rx and tx pins i can just write a sketch to flip the direction again?

so that means that i can use those two pins for now and still upload sketches right?

Did you miss the part about not using the pins for serial AT ALL?

You will need to disconnect whatever is connected to pins 0 and 1 in order to upload a new sketch to the Arduino.