I have a T510, and the nvidia driver loads fine for me (I'm testing the latest Natty).  I do have the Display changed in the BIOS to tell the system that I have the nvidia graphics ("Discrete") rather than Optimus.  Maybe your BIOS is set to Optimus?

However, once I have the nvidia driver going, the information for my displays is not right.  The displays are reported fine under the nouveau driver, so there is something about the nvidia driver that makes things like xrandr unable to query things.  For instance, the Monitor utility reports just a single display tagged with "Unknown" even with an external display plugged in.

Here is the xrandr info with the nvida driver (note the opening error and the use of "default"):

xrandr: Failed to get size of gamma for output default
Screen 0: minimum 320 x 175, current 1920 x 1080, maximum 1920 x 1080
default connected 1920x1080+0+0 0mm x 0mm
   1920x1080      50.0*    51.0     52.0     53.0  
   1680x1050      54.0  
   1600x1024      55.0  
   1440x900       56.0  
   1400x1050      57.0  
   1360x768       58.0     59.0  
   1280x1024      60.0     61.0  
   1280x960       62.0  
   1152x864       63.0     64.0     65.0     66.0     67.0     68.0  
   1024x768       69.0     70.0     71.0     72.0     73.0     74.0  
   960x720        75.0  
   960x600        76.0  
   960x540        77.0  
   928x696        78.0  
   896x672        79.0     80.0  
   840x525        81.0     82.0     83.0     84.0     85.0  
   832x624        86.0  
   800x600        87.0     88.0     89.0     90.0     91.0     92.0     93.0     94.0     95.0     96.0  
   800x512        97.0  
   720x450        98.0  
   720x400        99.0  
   700x525       100.0    101.0    102.0    103.0  
   680x384       104.0    105.0  
   640x512       106.0    107.0    108.0  
   640x480       109.0    110.0    111.0    112.0    113.0    114.0  
   640x400       115.0  
   640x350       116.0  
   576x432       117.0    118.0    119.0    120.0    121.0    122.0    123.0  
   512x384       124.0    125.0    126.0    127.0    128.0  
   416x312       129.0  
   400x300       130.0    131.0    132.0    133.0    134.0  
   360x200       135.0  
   320x240       136.0    137.0    138.0    139.0  
   320x200       140.0  
   320x175       141.0

And here is the xrandr information when I'm using the nouveau driver (note that it finds my external monitor and gets the labels right):

Screen 0: minimum 320 x 200, current 3840 x 1200, maximum 8192 x 8192
LVDS-1 connected 1920x1080+1920+0 (normal left inverted right x axis y axis) 344mm x 193mm
   1920x1080      60.0*+   60.0     50.0  
   1920x1080_60.00   60.0  
   1680x1050      60.0  
   1400x1050      60.0  
   1280x1024      59.9  
   1280x960       59.9  
   1152x864       60.0  
   1024x768       59.9  
   800x600        59.9  
   640x480        59.4  
   720x400        59.6  
   640x400        60.0  
   640x350        59.8  
VGA-1 connected 1920x1200+0+0 (normal left inverted right x axis y axis) 518mm x 324mm
   1920x1200      60.0*+
   1680x1050      60.0  
   1400x1050      60.0  
   1280x1024      75.0     60.0  
   1440x900       59.9  
   1280x960       60.0  
   1152x864       75.0  
   1024x768       75.1     70.1     60.0  
   832x624        74.6  
   800x600        72.2     75.0     60.3     56.2  
   640x480        72.8     75.0     66.7     60.0  
   720x400        70.1  
DP-1 disconnected (normal left inverted right x axis y axis)
DP-2 disconnected (normal left inverted right x axis y axis)
DP-3 disconnected (normal left inverted right x axis y axis)