This post provides a list of more than 20 resources that can be used in sketching phase of application development categorized as follows:
Printable sketch templates for websites
Printable sketch templates for mobile applications
Sketch Books
Make you own sketch templates
A Collection of Printable Sketch Templates and Sketch Books for Wireframing
I heart wireframes is a collection of user contributed wireframes.
I ♥ wireframes
This article describes the following about wireframes:
What are they?
Why do we use them?
When should they be used?
What are the different types?
How are they used in a project life cycle?
Why are they important?
The what, when and why of wireframes
If you don’t want to read the post, you can choose to watch a 5 minute presentation of [...]