In Bangkok.............. where to go and what to see?

I have a friend coming to Bangkok for 4 days, female. Any recommendations for things to do while here?

Also do any of you know a reliable and trustworthy Tuk-Tuk driver who will drive them around for the day and take them to places of interest for a set fee each day?

Many thanks for any advice.

Have a browse at wikitravel.

Start out at Soi Cowboy and work your way down to Nana. there is little else in Bangkok a female traveler would be interested in seeing. The tuk tuks in that area are all very reliable.