If you login and have "Remember Me" selected, you shouldn't have to login again. I browse IceInSpace from a few computers and don't have to login.
Selecting "Remember Me" sets a cookie on your computer. So if it's not saving the cookie, you'll have to login every time you visit. Have a look to see if your browser hasn't disabled saving cookies.
If you forgot your password, you need to either reset it
here or PM me and I'll change your password for you manually. We can't tell you what your current password is, we can only change it to something else.