Source: http://vr-zone.com/
We found a driver released by Dell themselves (DELL_U2711-MONITOR_A00-00_R247058.exe) , dated 30th November 2009 on their own Support site.

Upon taking a look at the driver files, it is noted that the U2711 has:

- VGA output
- DVI output
- HDMI output
- DisplayPort output

And the resolutions of the panel:

[1920]
HKR,,MaxResolution,,"1920,1080"

[2048]
HKR,,MaxResolution,,"2048,1152"

[2560]
HKR,,MaxResolution,,"2560,1440"


It's probably firm that the panel on the U2711 would be the same one found in the 27-inch iMac.



That display is a LG LM270WQ1 16:9 IPS panel with LED backlight, and has a massive 2560 x 1440 resolution.
Ooh, LED backlight, more affordable than 30 inchers, and a pretty high resolution - awesome!