Well, you can, of course, also upgrade to a T7400 as well as the T7600...
But no, your motherboard is incompatible with the newer Core 2 Duo processors with the 800MHz FSB (i.e. T7500, T7700). You can't upgrade your motherboard because, well, there's no motherboard out that can fit the M2010 that supports these chips... Currently, Dell only offers the Inspiron 1520 and 1720 along with the XPS M1330 that support these newer, 800MHz FSB chips.
When/If Dell decides to release an update to the M2010, its HIGHLY UNLIKELY that the upgraded motherboard will fit in your unit.
Long story short, if you want to upgrade your processor, the ONLY options you have are the T7400 and T7600.