Yes, in the MobilePre control panel you can un-mute the Direct Monitor channel, raise the volume to 0, and the input signal will pass directly (zero-latency) through the outputs. You will still be able to hear computer playback at the same time.

Please note, if you hear a double-echo when you enable this, most likely your software is also passing the input signal through its own direct monitoring (with latency). You'll want to disable this in your software. For example, in Sonar, go to Options-Audio-Input Monitoring and disable all channels of Input Monitoring. In Cubase/Nuendo, go to Devices-Device Options-VST Multitrack and uncheck Direct Monitoring and click Apply.