I remember my first Nokia..

http://www.mobile88.com.my/cellphone...40/preview.asp

It had a fixed LCD screen, not a dot matrix display.. Icons were fixed graphics.. and it had a fixed voice mail spool icon.. not a image that is generated in software, a hard indicator..

These voicemail icons have been around since 1995 at least..

Some networks use them, others don't and some are hybrid and have introduced them recently.. I believe Vodafone in the UK recently allowed users to use the spool icons on their phones..

It is a bit of a shame it isn't present on the N900.. much like it is a shame MMS isn't there.. but really it should be miles easier to add this feature than MMS!