SD Reader Writer and Atmega328 -- Level shifting?

I'm attempting to build a data logger board using the programmed chip off of an Arduino Uno.

As many others have done, the plan is to log the data on an SD card. I've got a RobotBase SD Card v3.0 and I don't recall where I purchased it. A search for a datasheet in English or other technical documentation has been fruitless.

The question I have relates to converting 5v to 3.3v. The RobotBase board has an AMS1117 5v to 3.3v regulator on it. I'm assuming this means that it can take 5v at Vcc. But does it also level shift the data lines coming in or do I have to convert those signals down to 3.3v with something like a 74LVC245?

Yeah, not only the power needs to be dropped for the 3v3 SD card, but the logic levels must be shifted to 3v3. I think it can be done with 4.7k resisters on all the data lines to ground (I think that the RobotBase is shifting the logic the same), but I like the 74AHC125:
http://www.nxp.com/documents/data_sheet/74AHC_AHCT125.pdf

Adafruit have a shield for that:
http://www.ladyada.net/make/logshield/solder.html

I have not put the data-logger together yet, but the simple WAV Shield works perfectly to expectations (no RTC and battery on the WAV shield).

Thanks for the quick response. But I am a bit confused by it -- are you saying that you think the RobotBase card has a built-in level shifter? If that is the case then there isn't any need for an external part, right? Could you clarify.....

You need to look at your RobotBase board and confirm you have a voltage divider (4k7 sig/data and 10k gnd) on SCK/CK, MOSI, SS/CS. MISO does not have a divider. If this is the case, you are ready to go.