Hi Wafel,
Definitely! There is one hardware UART that is also used by the USB to program it. In addition, you can use the Arduino SoftwareSerial to make any other pins on the TinyDuino (which is basically just a shrunk down Arduino Uno) into a software UART. This is what we use for a number of our TinyShields that use UARTs, include the GPS TinyShield.
Thanks,
Ken
TinyCircuits