My ipod touch wont connect to my linksys router any help?

I have a linksys router which i used to be able to connect my ipod touch to but for some reason it must have disconnected, now i cant reconnect to it with my ipod touch (2 other laptops on the network connect fine). This is really annoying me!! any help please!!!! any questions feel free to ask as i really want to get back onto the internet on my ipod!! thanks!!