I rooted my HTC Desire 2.1 and I want to turn in into secure access point.
Is there any way I can do that?
I do want to make is secure so user has to enter password to get Internet access.
Depending on what device you're using, Android Wifi Tether might work for you. It's also in the Market, but the Google code page has the most recent versions . It supports WEP, WPA, and MAC address filtering (they refer to this as "access control"). You may need a custom kernel for it to work - this again depends on your device/ROM.
You could also try one of the several other wireless tether apps that are currently in the Market. Some are free and some are not, but you can shop around a bit.
Yet another option would be to install CyanogenMod if your device is supported, since it has the AOSP wifi tethering built in.