The city centre is generally safe at the time of writing this entry Nov 2009. It is not a problem to walk around, locals are not so pushy to sell stuff or beg for money however sometimes it happens. Always carry your passport with you, but not too much money if you're on foot.
A colour photocopy of your passport can be certified at the Hotel de Ville for a few dollars and is much safer to carry around than your passport.
Travelling with your own transportation is not a problem, even at night time, there are street lights almost everywhere in the downtown.
telecommunications
Four GSM-900 mobile telecommunications companies, Telecel CAR, Nationlink Telecom RCA, Orange CAR and MOOV CAR operate out of Bangui. State-owned Socatel is the principal telecom in CAR and Bangui, and is responsible for the operation and maintenance of the communications infrastructure.
Internet cafes in town allow users to access the internet, also using own laptop computers. Download speeds are acceptable and prices reasonable. MOOV provides GPRS/EDGE internet access with USB sticks for reasonable prices in whole Bangui and in major cities of CAR as well.
Le Grande Cafe in the city center has open free wi/fi and serves coffee and food.
MOOV and Orange phones can access GPRS/Edge networks if properly configured. Configuration is provided free at the telecommunication offices at PKZero. Speeds are generally EDGE, but may fade to G. GPRS is available in Bangui center, but fades out by PK12.