Getting around Panama City can be tricky at certain times of the day. There are several bus routes that essentially go along the city but the queues for these can be enormous during the rush hour (as many as 100 people). In addition, the buses tend to go to places you don't really want to visit.
The only other alternative is to travel by taxi and while these are numerous during busy periods taxi drivers are picky over where they take you: I have frequently spent between 20 minutes to more than an hour trying to flag one from Ancon to the El Cangrejo area. They also overcharge, especially if your grasp of Spanish is weak, and will not issue receipts so I suggest (a) agree a fare before you get in, and (b) if you need receipts, buy a receipt book from Office Depot or the Rey supermarkets. Taxis hovering outside big hotels will charge at least two to three times the 'normal rate' but they will provide receipts (usually). In summary, just be patient!
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