if you have a belkin N1, you are doomed!
some things that work, if you know how to do them:
1.) some people have found changing the 802.11 protocol to single channel from 802.11n to 802.11g helps.
2.) you can also play with the security protocol of your router by testing wep, wpa, wpa2, tkip/aes.
3.) this person had no problems with the belkin n1 by setting his dhcp lease time to infinity, thus essentially making static LAN IP addresses. -which other people have found to help with all types of routers and other froyo devices (besides nook color).
4.) double check that you are entering your wireless security passcode properly
*after each change, you'll need to "forget" or delete your wifi access point on your nook color and reconnect to it.