As most of you might be aware of the fast pace development and popularity of Android OS on Smartphones you might like to try it on your phone too,
Android is linux , and as with every linux distro there are always a good no. of developers trying to make something better( eg: Mint was built on ubuntu , and ubuntu is based on debian) same is the case with android,
If you search through the net you will got to know that there exists android builds for most of HTC phones and some Samsung phones too,,
A quick look On supported devices :
HTC : Touch pro, Diamond, Fuze, diamond 2, Touch Pro2, Tilit2 , HD, HD2 etc.
samsung:

  • Samsung i900 (GSM, supported worldwide)
  • Samsung i910 (CDMA, used by Verizon in the US)
  • Samsung i780 (Mirage)
  • Samsung i907 (AT&T Epix)


(if your phone is not on the list then try to google if it is supported..)

Now there are different teams working on this, so you might need to do some work yourself also,

I own a diamond2, therefore i will carry on with that as an example .
->
after some searching, i found that XDAndroid supports my device good enough, so started to digg that.
The site where i got to know about this thing first wrotes " It will not work on SDHC card, and you will need a microSD card(typically<2GB) only" but i had an 8 GB SDHC card but i still decided to carry on(I don't know why??).

the current stable release of XDAndroid(Eclair) was not working, but the Beta(Froyo) worked(im still on SDHC)!!
All you need to do is download the package file from the main site, extract it to your SD card root along with a START-UP.txt(available at the same site of package directory).

And then run Haret.exe from file explorer, It will just reboot your phone into Android, If youwant to start Windows again just restart your device as Android Is like a superficial OS, it will not make any change to your Windows System and write any changes you make in android to the SD card...

If you have tried it or have any question, Post a comment on yourexperience( i mean Reply to the thread )

Note: There are certain Hardware limitations which vary according to
the build, device, and releasing team, So be sure to check that..