I have the Telstra HTC Desire and want to upgrade to Android 2.2 without all the Telstra Apps.
Here are the steps I performed on the Telstra A8183 Desire (Note: I am using it on the Telecom New Zealand XT Network)
1.) If not already done, Install HTC Sync and restart your computer (Yes you actually do have to restart or it wont work)
2.) Format the microSD card to FAT32 format (quick format is OK).
3.) Put the microSD card in your device and boot it.
4.) Launch GoldCard Tool (Right Click and run as Admin if needed)
5.) Connect Android device to USB and enable USB Debugging (Settings --> Applications --> Developer --> Enable USB Debugging)
6.) Click 'Get CID' (If MMC1 fails try MMC0)
7.) Navigate to http://psas.revskills.de/?q=goldcard, enter the CID number from Goldcard Tool and create your Goldcard image, which will be e-mailed to you.
8.) Enable USB Mass Storage on the Desire if its not on already
9.) Click 'Refresh' and select your microSD card in the drop down menu.
10.) Click 'Load GoldCard.img' and open the .img file you got by email.
11.) Click 'Patch MMC'
12.) Download and run RUU_Bravo_HTC_WWE_1.21.405.2_Radio_32.36.00.28U_4. 06.00.02_2_release_126984_signed.exe
13.) Once the phone is flashed, download OTA_Bravo_Froyo_HTC_WWE_2.09.405.8-1.21.405.2_release4dua3bcrut4wrv30.zip and rename it to update.zip
14.) Copy it to your Goldcard and power off the phone
15.) Turn on the phone by pressing the Down arrow Key and the Power Button This will take you to a menu. Using the volume down button to select recovery mode and press the power button.
16.) When you see the image of the phone with an Exclamation mark press the volume up and the power button and select install the contents from update.zip