What's FLV?
FLV is the short name of flash video. Flash Video is a file format used to deliver video over the Internet. Because of the small file and fast loading speed, it is possible for us to watch video through internet real time. Most of the popular online video sites like YouTube, lulu, MySpace use FLV as the video format. The videos we watch or download from these sites are all FLV formats. After Google bought YouTube, FLV becomes more vividly than ever in nowadays WEB2.0 times.
But, these FLV Video can't recognized by iPod for iPod only supports MP4 Video files, so we need the third party software to convert those downloaded FLV files to mp4 to play on iPod.
Here I recommend you to use a good FLV to iPod Converter - Video Converter Ultimate which is the best video conversion tool(Windows 7 Compatible) I am now using. By viewing this passages you will find that it is very easy to put and play FLV Video files on iPod Players.
Here is the step by step way to convert FLV to iPod MP4 and transfer FLV to iPod.
Import FLV file. Click "Add Files" to import FLV Video files into video converter. Or you can easily drag & drop files into the window. By the way, it can convert FLV video files in a batch.

Click "Edit" button, you are allowed to make wonderful video editing like adding rummy effect or watermark, even you can crop or trim the video.
Choose the output modules that have been designed for you. IPod touch, iPod Nano and iPod classic are all included. You shall select the most suitable one for you.

Click the "stat" button and then enjoy it. You will get a high speed and good converting quality that you want
Transfer the converted video to iPod. It is just like what we usually do. Launch iTunes, click File option on menu, and add your converted files to iTunes library. Then, connect your iPod to computer via USB cable, iTunes will detect your iPod. After that, click iTunes "File -> Sync iPod", and the files will be transferred to your iPod from iTunes library. When updating completed, you will find the videos on you iPod.