Hi Amy Gi
After upgrading my iphone to the ios6 people who had access to my wireless network, found that their phones kept diconecting them from the said network. After trying almost all permitations I think the one that worked for me was as follows.
1.Make sure all devices using your network have the latest ios system
2.Reset your router and set up as normal, ie setting up password network name etc
3.Attach each device to the network using the correct password
After I completed the above steps everyone who connected to the network has been connected ever since.
I think my netgear router was getting confused after everyone upgraded their ios system.
When I reset my router I gave it a new network name and also changed the password, as I said since doing ths the equipment ie 7 iphones 2 ipads apple tv and macbook pro have not dropped a connection since.
Good Luck