Transaction Log Reader

No, there does not.  The log cannot be read.  The closest thing to reading the log is to query the INSERTED and DELETED tables through a trigger.  If you need to read the log to track what is goin on you could create triggers on the tables.  The triggers could query the INSERTED and DELETED tables and write the results to another log table that you create.  You could also add a date/time stamp field to track when the activity happens.

But should it not be possible to read the transaction log backup (the SQL Restore can read it ?! )

You mean is it possible to restore the log?  Yes, of course.  If not there may be some other problem, like corruption.  You may have to restore the database and log together that were backed up at the same time.

Let's turn the sentence the other way:
I have a transaction log backup, and i want to analyse it to find out who has done what operation BEFORE doing the restore.
The question is in fact to find out when the operation has been performed to be able to do the restore to the moment just before.
I know how to restore a (transaction log) backup, but i need to know to what moment before i do the actual restore.
Otherwise I would have to do test restores and find out what happend (which would take some time on the 1,4 GB database with over 100 tables...)

If I understand, you have a database backup with multiple transaction log backups between database backups.  So, you want to restore some of the transaction backups up to a certain point, which is yet to be determined.

If so, this is the reason for doing tranaction log backups.  You restore one at a time until you find the point where some problem occurs (or just before that point).  So, there must be some tell-tale sign of whatever it is that you are looking for - like some record got deleted.  So, if it is a flag record like that, you will have to restore each log and check that flag each time.  When you've restored one too many then you know the previous log restored is the one you stop with.  Then you have to kill the database and run the restore process again.  Perhaps you already are aware of all this.  But, if you could just read logs to determine at which point something happened, don't you think that would be a known procedure and required reading for training?  It sounds like a revolutionary concept that would advance the restoration process beyond it's present state.  I doubt there is any way or third party utility to do this.  

I understand that there seems no SQL Server external tool to exists able to analyse the log backup, even if SQL server knows internally how to do :-(
If you fall over such a tool, it would be great if you informed me.
Thanks

Yes, a tool exists for reding transaction log records. It is Lumigent Log explorer. If you want more information about it, send a mail to veyselc@banksoft.com.tr