cnbc.com gives you real time quotes free but you can't enter a portfolio.
google
yahoo
Fidelity Investments has lots of features but I believe you have to have an account.
I dig myStocks for a quick view. It's not free, or the most featured, but the UI is very simple and nice looking and it doesn't have a lot of bloat (only 142kb).
I only wish one of these had alerts..toysoft has an alternative stock alert app (Stock Icons) that vibrates on a specific price, but looking for more of a sound/popup.
There in tinystocks app that has alerts but the gui is horrible as well as the price of 30.
+1 Bloomberg. Quotes, financial news, and some really nice features like hyperlinks all over the place, ways to get to the latest financials for companies, and automatic ticker search when you use the keyboard. Very well though out, if not documented much.
It shows you info about all of your stocks, plus the important indexes from around the world.
You can check your stocks by for example double clicking the Space key from BlackBerry Home Screen or by for example double clicking Convenience key from any other app.