When using VMWare in Unity mode, Dock icons and icons shown when using Command-Tab, show up highly pixelated. This can easily rectified with a quick and dirty replacement of the icon.
First locate quality replacement images with transparent backgrounds. For instance, use Google images, and run a search on, for example, Internet Explorer icon. I look for icons that are about 300x300 pixels in size or larger. I drag the image to the Desktop and open it with Preview, using a background colour other than the white used on Google Images, so I can quickly determine if the images have a transparent background.
Once opened in Preview and deemed acceptable, go to Edit » Copy to copy the image to the clipboard. Locate the relevant .vmwarevm virtual machine file -- typically you'll find them in a Virtual Machines folder in your user's Documents folder. Control-click on the folder and choose Show Package Contents from the pop-up menu. Then go to the Applications folder within the newly-opened window to access your virtualized apps.
Choose Get Info on each app you wish to change. Click once on the icon in the upper left corner of the Get Info window (you will see a small shadow around it indicating it is highlighted). Now do Command-V to paste the image saved to the clipboard.
Repeat these steps for each program you'd like to change. If you wish to resort back to the original icon at some point, just go into Get Info again, highlight the icon, and press Delete.
Mac OS X Hints
http://hints.macworld.com/article.php?story=20080614210804414