I ran across an interesting application over the weekend while I watched it snow. AC-S2.com offers a "slide to unlock" application, S2U2, that is feature rich and freeware. The application does resemble iPhone's slider but S2U2 has a good amount of customization that includes the display of upcoming appointments, slide to answer feature, and customized wallpaper. The S2U2 settings menu is located in your programs screen under the S2U2 folder and is touch scrollable.
The AC-S2 website has a FAQ section as well as a downloadable description of each setting.It is freeware and a "use at your own risk" type application but I've had it installed for the past few days on an HTC Fuze with no problems. XDA Developer Forum member "A_C" created this application and website.
If you're looking for an alternative to the traditional screen lock for your Windows Mobile phone, S2U2 is definitely worth consideration.
Follow Up: If you are using an HTC Fuze and choose to load the Test ROM you will need to disable S2U2's Caller ID/Slide to Answer feature. It conflicts with the Test ROM's slide to answer feature and locks up the Fuze.