DDos attack on my forum?

[iHatton]

I believe a ddos attack is occurring on my forum.

At the moment, I am getting multiple connections (about 50 - 100) from around 50 different IP addresses. Both numbers grow every minute.

All the IP addresses I traced back seem to come from ;

IP country code: US
IP address country: United States
IP address state: Florida
IP address city: Lake Worth

That is most of the locations, however some are from different areas of the US, and some are from the UK.

Is there anyway to stop this attack?
How long do you think it will last?