How do you manage multiple passwords?

Hi,
I have a question. How do people manage multiple passwords?
I for e.g, have same for many sites which I dont mind losing.
Different passwords for serious ones:
- Admin account for my office comp.
- Citibank account.
- Airtel bill payment.
- Different TPIN
- etc..

but many a times my passwords are within a group which I use.
My problem is, I often forget passwords if I employ a new one.
For e.g I forgot the Airtel site password again yesterday and did the forgot password thing ( this is the third time). I have lost citi TPIN as I have never used it.

What your ways of userid/password maintainence?