I believe you are able to go online with any other wireless computer with the wireless network that you have, first you need to check are you abel to see the wireless network name in your ipod touch, if yes and if your network is security enabled then you need to punch in teh security code for teh network and if you are not aware of it you can find it by follow the steps which are mentioned below
a. you need to be on your computer which is working on the internet, Open the internet explorer
b. type in 192.168.0.1or you can type http://routerlogin.com
, it will prompt you for user name and password, the user name will be 'admin' and password will be 'password', make sure you type it in small case
c.On the left hand side their is blue coloum and under the heading of Setup the third option will be wireless settings and their you can see the password of your wireless network as key 1 or if it mention as passphrase so it will be like '******', so you have to change teh wireless settings.
d. before you change the settings you make sure you are not doing all these steps on wireless computer if yes before you go further connect your computer wired
e. Once its done , Now you can change the wireless settings...., AS IMAGE BELOW
1. you need to chnage the wireless network name
2. CHANNEL you need to chnage it to 11 and if its 11 change it to 06
3. MODE should be b&g
4.security , i would suggest you WEP and in key 1 you can type any 10 digit number like you phone number or you can use teh same number i have mention in that screen shot
5. Click on apply and then try to connect with your ipod touch first along with the you need to connect you wireless laptop again for that you need to check are you able to see you new network name
6. Try to connect with that network , it will prompt you for password, you need to type the 10 digit code you mentioned in Key1 option on that page.
I think by follow all these steps you will able to connect you ipod touch and any other computer in your network again.