The iPad is en route, never forget that.

Per the mighty City AM, wireless carrier O2 is apparently negotiating with Apple for a U.K. 3G wireless data deal for the device. The 3G-compatible version of the iPad will ship as an unlocked device so users can pick their favorite carrier, although Apple is working with vendors to set up incentives and special deals.

Apple’s deal with AT&T offers tiers in which users receive 250MB of 3G data access per month for US$14.99, or unlimited 3G wireless data for US$29.99 a month. Both plans include unlimited Wi-Fi access at AT&T hotspots, and users can sign up for and cancel the service on a monthly basis without incurring extra fees.

Apple plans to start shipping the Wi-Fi version of the iPad in March, and the Wi-Fi plus 3G models should begin shipping about 30 days later.