Flowcharts are a visual technique for exploring and communicating the path a user takes through an experience. Representing the experience in a hierarchical format can help a UX designer explore the navigation scheme. Visualizing the flow forces the designer to identify hierarchies, content relationships and the distribution of content. Flow diagrams reveal the balance of the content elements and cross-linking opportunities. They can also be helpful in revealing complexity and demonstrating imbalances.
Flow diagrams are an important tool for recognizing and committing to the user experience but also for communicating the experience to the development team to ensure the flow is understood. They can identify an overall scheme but are also useful for mapping individual paths that require user input.
A wireframe is a schematic view of a page. It is typically created to identify the elements on a page and the relationship among them. Wireframes typically are proportionate to true scale so you can see the relative size of elements. Wireframes are usually done in gray scale and intentionally do not address visual design issues so the focus is on identifying the elements on a page and their relation to each other and those sizes and relationships are not distracted by color, typography, photography or illustration.
Starting Out Organized: Website Content Planning the Right Way by Kristin Wemmer in Smashing Magazine
Here are some sample archives to look at:
AIGIA Design Archives
Google Art Project
MOMA Exhibit: Color Chart
Movie Title Still Collection
and here’s a list of museums that have digitized their collections: