Since the invention of 'desktop publishing' in the 1980s, Adobe has been the industry leader in graphics-related software. Their flagship product -- Adobe Photoshop -- was introduced in 1989 and remains the dominant image editing software available.
In addition to Photoshop, Adobe's Creative Suite, currently in version 2, consists of a number of other design programs. The company is expected to release Creative Suite 3 in mid 2007, which will include the popular web design software Dreamweaver, which Adobe acquired from Macromedia in 2005.
While Adobe is not the only design software out there, the majority of schools, firms, and freelancers ultimately want to be on the same page. It is for this reason that Adobe monopolizes the industry and continues to buy out competitors.
Photoshop is the world's leading digital bitmap and image manipulation software. It is the industry standard for photo retouching and processing, and is largely responsible for many innovations in digital photography.
Illustrator is a vector-based drawing program. Illustrator is suited for page layout, typography, logos, sharp-edged artistic illustrations (i.e. cartoons, clip art and geometric patterns). Vector images can be resized without loss of quality, which is required in certain areas of design.
InDesign is intended for page layout and desktop publishing. Unlike Photoshop and Illustrator, InDesign was launched in 1999 as a competitor to QuarkXPress -- the industry leader at the time (and software that is still preferred by some designers). It initally had difficulty converting users, but since its incorporation into the Creative Suite, it is quickly becoming the new industry standard in page design.
Dreamweaver, created by Macromedia in 1997 but now owned by Adobe, is a WYSIWYG (what you see is what you get) HTML/XHTML/CSS editor. Dreamweaver allows users to design websites much as they design traditional pages. Designers still have access to advanced coding, but overall, Dreamweaver does much of the hard-coding work automatically.
Formerly owned by Macromedia, Flash is a multimedia designing program used to create dynamic content for the web. Since 1996, Flash has been the industry leader in web-based movies and animation, and is a common way to add interactivity and animation to web pages. Adobe will most likely include Flash in its next release of the Creative Suite.
Unfortunately, because of its professional quality, design software is usually very expensive, ranging from $1,500 to $3,000. Fortunately, numerous retailers give educational discounts to design students. Visit Adobe Education for more information.