What is Sharepoint?

Introduction to Sharepoint

(1) What is Sharepoint

(2) Introduction to Microsoft Office SharePoint Server 2007

(3) SharePoint for Developers: 1. Introduction

(4) SharePoint 2010 

(5) Getting Started with SharePoint Development

Sharepoint requirement
(1) Hardware and software requirements (SharePoint Server 2010)

(2) System Requirements for Windows SharePoint Services 3.0

(3) Preliminary system requirements for SharePoint 2010   

Important Links
(1) MSSharePointDeveloper Content

(2) SharePoint Development and Programming FAQ