Flash is a popular authoring software developed by Macromedia (now Adobe), it is used to create vector graphics-based animation programs with full-screen navigation interfaces, graphic illustrations, and simple interactivity in an antialiased, realizable file format that is small enough to stream across a normal modem connection. Flash is the professional standard authoring tool for producing high-impact Web experiences. Whether you are creating animated logos, web site navigation controls (buttons, menus etc.), long-form animations, entire Flash website's, or web applications, you'll find the power and flexibility of Flash ideal for your own creativity. Flash comes in SWF ( Shockwave Flash file) format and can easily be inserted into your web authoring tool (Dreamweaver, FrontPage etc.) Adding a Flash Intro (Introduction) to your website can give it that dynamic and professional look, which can lead to visitors returning, buying products or telling others about your site. Finding a website that actually offers FREE Flash Intros is hard but I have found a couple great one's at Flashfair and a FREE online Flash builder at Barend. To view some examples and tutorial see below:
EXAMPLESTUTORIAL
STEP 1:
For this example we are going to make a Flying Text Intro. You will need to download the Intro, click here. Then unzip the Flying Text intro to your website folder.
STEP 2:
Open the flying_text file. You will need to edit this file and add your own text and website address.

Make sure this file is saved in the same area as the rest of the unzipped files.
Test your Intro in your browser by selecting the 1flyin_text.html file. As the Flash intro is the main HTML (1flyin_text.html) page, predominately it is saved as index.htm.
OTHER TUTORIALS
Webmonkey
Anim-fx.
Siteownersdesign