Bulk add users.

I have my recently moved away from my old CMS to wordpres and I have to say im loving it, few small problems but nothing major.

I have compiled a massive e-mail list from me old cms database file, and I would like to add them to our wordpress install is there an easy way to go about this ?

Ideally, I just want to supply the address, and then have the system mail them with a password, and have the address be their login, I am correct in assuming that when they login they would get asked to supply a nickname which would then be displayed on blog ?