ok i think i could help here as just did it myself (however credit goes to all other people who helped me):
to Crist and guys at XDA for this (this one with official Froyo and no root needed):
how to save apps on SD CARD:
if u can complete the following steps u can then save most of your apps to the sd card .
i am able to now move most of my apps to the sd card .
I just spent an hour figuring this out.
and get the SDK for your OS
-Once you download it, unzip it to its own folder, I put it off C:\
-Run the SDK Setup.exe
-Click available Packages, on left, install all the packages for froyo 2.2. Although I do suspect that we only need the USB driver, which is at the very bottom.
It will take forever to install.
After it's done installing, I Clicked on Installed Packages, and update all.
Not done yet.
check that the phone is set up to allow debugging via USB (Settings⇒Applications⇒Development⇒USB debugging)
Plug in your phone
will fail to install the driver.
Go in device manager and and update the newly Yellowed entry, the driver is in:
C:\android-sdk_r06-windows\android-sdk-windows\usb_driver or your original downloaded location
The driver should install
then open command prompt in windows .(type cmd in run line or click start and look for run )
cd C:\android-sdk_r06-windows\android-sdk-windows\tools or where ever your original sdk is unzipped .
and then type
> adb devices
if you see a serial number starting with an "H" that means you got things working, now do the following:
> adb shell pm setInstallLocation 2
This command will push ALL apps to your sd card .
you will see that the button for move to sd card will now not be grayed out and u will be able to move apps now to sd card .
to reverse the above type
> adb shell pm setInstallLocation 0
just did everything myself and it really does work (how incredible is that). had 7mb left of free space and now after moving some games and apps to sd card i have nearly 50mb (yuhhooo). however not all apps like being on sd (handscent sms) so moved it back to internal memory
so check apps as you move them to sd card if they work properly,ok?
and when you do enter adb commands please just copy them from here and paste otherwise can make spelling mistake and won't work. moreover when you enter command enabling apps2sd button to be active the command wont give any confirmation or error so just check your phone if it's working.
another tip if you;re tired of entering commands just copy cmd.exe from original windows system folder and paste it to your sdk folder and into tools folder and run it from there so will save yourself a bit of typing and nerves
and thanx HTC for Froyo