Here is a work outfit I put together for myself. The top is from Nordstrom. It is a red jersey with a peter pan collar. It matches my rose print capri pants from Wal-Mart. I added silver shoes by Coach to make the black, white and red look current and in season.
This is a really good example of an appropriate work outfit for summer. I know it is really hard to look appropriate and feel comfortable at work in the summer; I have lived in Texas most of my life!
A tip to keep cool at work is to not hesitate to buy summer work clothes where ever you find them. Being appropriate for work is more important than a brand name; although brand names are nice ;).