Why wait when you can install iOS 4.1 right away. No UDID is required, all you need is:

How to Install iOS 4.1:

Step 1: Download and install iTunes 10

Step 2: Download iOS 4.1 GM IPSW files for your device

Step 3: Plug your iPhone / iPod Touch to computer and sync with iTunes

Step 4: Select your device from iTunes sidebar, this will show device info summary.

Step 5: Press and hold Shift key (Windows) or Alt key (for Mac) and click on “Restore”. (Important: Don’t click on “Update” or “Check for Updates”).

Step 6: Now browse for iOS 4.1 IPSW that you downloaded in step 2.

Step 7: iOS 4.1 installation will begin. Let it complete, should work smoothly. If you face any problems, try updating while in DFU mode. Steps to load custom IPSW into iPhone can also be found here.