5v Arduino Pro vs. 3.3v SerLCD?

Yeah so I'm kind of a doofball. My Arduino Pro is 5v, but my SerLCD is 3.3v... so my question is this.

Can I run the arduino off my power supply 5v and run the SerLCD off a 2xAA battery pack as long as they share a common ground? Will the serial line not speak properly to a device of a different voltage?

I am new to arduino and am totally excited to get started tonight!

Maybe.

Does the SerLCD have 5V tolerant inputs? If it does then yes. otherwise you will need to use resistor dividers on all the output signal lines you connect to the SerLCD.

(* jcl *)

You may also want to check into something like this:

http://www.hvwtech.com/products_view.asp?ProductID=927

I have some of the LevelConverters from SF... they work quite nicely... Use them for both I2C (need to use both TX channels) as well as Serial...

Thanks a lot guys, I will look in to some level converters before hooking this thing up (cry)