As reported by Engadget, "Labeling for the attached (and apparently not removable) door on the back of the device indicates an SD card slot, which will sit right alongside a SIM card port."
Dell's M02M known features are 7-inch touchscreen display, Tegra 2 processor, 3G support (the listed UMTS bands II, IV and V indicate compatibility with both AT&T and T-Mobile), 802.11n Wi-Fi connectivity and Bluetooth 2.1 + EDR. Hopefully, this mobile internet device will be announced at the CES next month :) stay tuned.
[via Engadget]