FLV extension has been very popular, with youtube videos and flash videos being saved in .FLV format, it is necessary to have such FLV player application installed either on your PC or mobile phone.
For playing and watching FLV videos on PC – You can make use of VLC media player as well as SM player and the good news is that we also have a freeware FLV player with full version for Symbian S60 Mobile phones.
With the use of Nokia FLV player you will be able to watch flash clips and YouTube saved videos (.flv format) right from your mobile screen, this is an added advantage as the program built for Symbian 3rd edition phones and is very much useful.
Free Symbian S60 FLV Player
The FLV player works with only S60 3rd edition mobile phones. Here is the list Symbian FLV player supports:

FLV Player for LG Models: KT615, KT610, KS10
FLV Player for Nokia Models: 3250, 5320 Xpress Music, 5500 Sport, 5630 Xpress Music, 5700, 5730 Xpress Music, 6110 Navigator, 6120, 6121, 6210 Navigator, 6220, 6290, 6710 Navigator, 6720 Classic, E51, E55, E60, E61, E61i, E62, E63, E65, E66, E70, E71, E75, E90, N71, N73, N75, N76, N77, N78, N79, N80, N81, N81 8GB, N82, N85, N86 8MP, N91, N92, N93, N93i, N95, N95 8GB, N96
FLV Player for Samsung Models: I7110, INNOV8, SGH-G810, SGH-L870, SGH-i400, SGH-i450, SGH-i520, SGH-i550, SGH-i560
The FLVplayer is in .sisx format and has been uploaded to mediafire which can be downloaded from here

Working fine on my E51, i don’t understand why it doesn’t work on other people
Thanks for a great application!
It does not work on my mobile due to certificate error !!!
It seems that it is only a toy which you can see & do nothing in your daily life…
I request all of you not to download.
It is not sufficiently works in other phones also.
Its not working also for me….Very bad.