Lock screen is one of the most ignored part of the phone but at the same time you can do many things and get information right from your lock screen without opening your phone.
Here are some top lock screen apps fro your Windows Phone :-
Weather Flow
This app comes with weather experience tailored for Windows Phone 8 with amazing live tiles and awesome lock screen support. You can choose from two different live tile styles and three different live tile settings. Use the simple and elegant modern style or the graphical and beautiful rich style. Set the content of the live tile to show current, daily and hourly forecasts.
Hello Friends
If you love customizing your smartphone, you will definitely love Hello Friends. Hello Friends creates collages of your friends that you can use for your lock screen.
Photostream
Photostream update your lockscreen wallpaper for you automatically. Photostream allows you to set up photo sources from your local albums, Skydrive albums, Flickr, and 500px as a live wallpaper. Photostream is the most comprehensive live wallpaper app on the market, allowing you the most control over your lockscreen wallpaper.
At Countdown
You can keep track of a daily or hourly countdown to a significant date, like New Year’s Eve, a Wedding, etc with an updating Live Tile and Lock Screen background image. You can type a custom message and select the background image from your local pictures.