Does Facebook have some sort of API that I can make a client?

For example...I would like to make a "client". First, people post to my client, and then to Facebook.

(I want to make a cli开发者_JS百科ent so that I can store posts)

Facebook has a number of APIs, including ones which will allow you to do the thing you describe. The term "posts" is a little vague since that covers a number of things on Facebook, but as an example there is the Status.Set API Call you can be used to update a user's status.

A useful place to start would be the Facebook Developer Wiki.

You should try "Google" before posting a question. There's a portal for developing applications on Facebook called...

• Facebook Developers

By client API, I assume you wanted a "Desktop" client, if so you probably wanted the...

• Facebook Server API

...which you can use to add a post/comment, for example.

If your are targeting a .NET environment (ASP.NET, Silverlight, WM, ...) you should take a look to this toolkit: http://facebooktoolkit.codeplex.com/