You can buy rolls of vinyl sheets in craft/hobby store and tape them on. I know many people have tried this instead of painting it. I was a bit worried about painting it myself but after watching some videos on youtube, I took the plunge. I don't regret it for a second. I am actually painting my 10g and 15g this weekend(hopefully!!). I done it a while back on my 55g. It's not that hard really, just half empty the tank, turn it around as far as you can. I done mine with everything still inside, filter tube, heaters, décor and fish!!. I just turn everything off. You could do it in an about 90mins or less.
The vinyl does work but imo, the paint looks the best and you don't have to worry about it coming off....
PS.. It is very easy to do, very cheap, very cool and very easily removed in the future, if needed....