Being new to VS, how may I think of these two concepts, what is the difference?
A Solution can have many Projects.
The Solution can also handle managing the dependencies between its different Projects...making sure that each Project gets Built in the appropriate order for the final Solution to work.
A solution is a container for projects, and tracks dependencies between projects.
Solutions are containers for projects - you can also use them to organize items that are used across different related project (shared dll's and such).
Just to come up with a metaphor..
A solution is like a house, a project like a room. Each room provides a piece of functionality whereas the house, a container of rooms, provides the means to link the rooms together and organize them appropriately.
Kind of corny but I made it up on the fly, so bear with me :)
A project contains executable and library files that make up an application or component of an application.
A solution is a placeholder for logically related projects that make up an application. For example, you could have separate projects for your application's GUI, database access layer, and so on. The projects would be specific divisions for your program's functionality, and the solution would be the umbrella unifying all of them under one application.
See also: Programmers' Heaven