If you don't have money to invest in those expensive programs like Macromedia Flash, Macromedia Dreamweaver and Swish max and what you want is just integrating a .swf file made by someone else to your html pages you can use the below markup (code) to do it.
<object type="application/x-shockwave-flash" data="yourflashmovie.swf" width="xxx" height="xxx">
<param name="movie" value="yourflashmovie.swf" />
</object>
Replace your flash movie to the path and name of your .swf file
width and hight should be given in pixels.
This code should work perfect with all the major browsers (FF, Opera and IE) but some browsers might need the <embed></embed> tag too included.
Also this code should pass you error free in W3C validation for yor markup.