Won't Start, think I may have run battery down. Advice ASAP

[Nightsbane]

Have had my 2005 for about 2 months now and haven't had a single issue. I drove to a friends house tonight and when I attempted to leave the bike would not start. I had turned the key to turn on the power and then we got to talking and it was on for ten minutes, maybe 15. It would roll over, but slowly and quiter, and with each press of the ignition the roll over sound was quieter and slower. I am wondering if by this description you can tell me what has happened? My first thought was that I possibly ran the battery too far down sitting there with the light on. I have never had any problems with the battery, but I don't know how long they can sit like that with the power on. The previous owner also said he kept it on a trickle charge just in case, but hadn't had issues.

I was also due to get gas soon, but didn't think I was quite out. I flipped it over to reserve and tried to start to check, but it wouldn't start.

Let me know what you think. This is my only mode of transportation so I need to get this sorted asap. If I do need a charge what can I jump it with? How long should it run after? What kind of charger can I use? What volts/amps? Where do you access the battery terminals?

ANY and ALL help would be greatly appreciated, thank you.