yes, it is legal if the converter is developed by legal company :)
I think is FLV to Video Converter Pro 2. The best FLV to Mp4 Converter.
I always use Nidesoft video converter, this converter can convert flv to mp4 in high quality at fast speed, besides, it can convert between almost all oher popular video and audio formats. it is also easy to use, only a few clicks were needed.Convert any online flv / youtube video to iPod / zune / PSP / MP3 / MP4 Portable player directly.it is full free!!You can use moyea flv converter and FLV to AVI MPEG WMV 3GP MP4 iPod Converter V4.2, both of them are professional FLV converter software which can convert Flash Video FLV to AVI, FLV to MPEG, FLV to WMV, FLV to 3GP, FLV to MP4, FLV to iPod, etc.
uSeesoft FLV Converter can do it for you it can convert FLV and YouTube videos to almost any video/audio format with unmatchable conversion speed and high quality, such as converting FLV to WMV, converting FLV to AVI, converting FLV to MP3, converting FLV to MPEG, converting FLV to MP4, etc.
You can convert Shockwave Flash (*.swf) files into Screen Saver files (*.scr) using a program like InstantStorm, see the related link for their homepage.With a FlV converter, convert FLV or .swf files to gif or aiv.http://www.sharewareguide.net/article/Tip/avi-to-flv-converter:-how-to-convert-avi-to-flv-file.html
Search a normal flv converter or a video converter ultimate It supports convert FLV file to popular video formats including AVI, MPEG, WMV, DivX, Xvid, ASF, 3GP, MP4, iPod, PSP, Zune and convert FLV to audio formats MP3, WMA and WAV.
I just found this thing called flv to wmv video converter (it's for mac, if you need windows get FreeStudio and use 3GP video converter) it's free.
You need two things: a flv encoder and a web-based flv player. Why? Because a flv encoder is used to convert your avi to flv and a web-based flv player is used to play the resulting flv on website. First thing, flv encoder. Good and free flv encoder like Moyea Video4Web Converter, which you can try. The second thing, flv player. You can use playerdiy.com, it is a quick way to make flash video player for website. On mac, Doremisoft AVI to Flash converter for mac makes these tough work easy by a few steps. With mac AVI to FLV converter, you are allowed to convert the common format AVI to FLV(flash video), convert AVI to SWF and generate a HTML web page embedded with Flash video.
You need a video converter for .flv to .mp4.Download the Enolsoft video converter or Koyote Soft Free Video Converter 2.3.http://download.cnet.com/Enolsoft-Video-Converter/3000-2194_4-75755915.htmlLocate and add the .flv file you wish to convert to .mp4. Follow the conversion instructions ensuring your Output Format is .mp4.
Here is a guide about how to convert FLV to WMV, same way to convert FLV to AAC because Daniusoft video converter support convert FLV to AAC too.
Google "FLV Converter for Mac" and find (buy) some software that you install; follow the manual.
Throw your .flv files into a converter program like Free HD Video Converter Factory or VLC (if you'd already have it installed), and choose WMV format to make the conversion.
Just three steps to do the trick:Step1. launch the DVD to FLV Converter and import DVD files.Step2. Edit the DVD video (Optional).Step3. Start conversion.