Below are some sample formulas for SSRS fields. I've found that they're not all that intuitive. I know that you can Google them, but it's easier for me to blog them here, and then look on the menu for them when I'm developing.
Included below are formulas for bolding and changing fore/background color. I'll add more if I need to code them.
Take a second and look on the menu above: Knowledge Base > SQL Reporting Svcs, then search for (CTRL + F) 'sample formulas'. Easy Peasy.