From what i know flr is further leave to remain and is used once married if you arrived on a fiancee visa but i have heard it written as limted leave to remain as well.
ILR is indefinte leave to remain can normally be claimed two years after arriving in the UK.
You need to show evidence of living with your spouse together as a couple ie bills and letters sent to you as a joint couple or to either of you.
Best to have a read of the set(m) form but be aware the amount of evidence required can change in 05 and before you only need 10 pieces of evidence and now you need 20 pieces from 5 seperate sources spread out across the 2 years of you being in the UK.
Have a bit of a search on here and on google but as i say look for the latest info as the rules change now and then and best to just read current info.
