Do later acts in inferno drop better gear?

Solution 1:

The above information is no longer correct once 1.03 comes out. The proposed changes are:

The proposed changes can be found here.

Solution 2:

Update: As posted by Halfwarr, Inferno drop rates were changed in 1.0.3. The highest level gear can now drop from any Inferno Act, but later Acts will have a higher chance for the higher item levels.

Yes.

Even though the requirement will be level 60 on most Inferno stuff, the actual item level will differ on different items. A higher Act will have the possibility of dropping higher level items than lower ones.

For instance, the max item level you can find in Inferno Act I is 61, while the max item level in Inferno Act II is 62. Act III and IV both have 63 as the maximum.

This is because maximum possible item level directly depends on monster level, and monsters on Inferno are higher level in the later Acts.