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Cucusoft Ultimate Converter Suite converts all the media file to play on almost any portable device including iPod, iPod touch, iPod video nano, iPhone, Zune, PSP, video capable MP3 players, video capable mobile phones, and Pocket P.C., etc. Meanwhile, it can also support output almost any audio/video format including Video format(H264, MP4, WMV, AVI, MOV, RM, 3GP, flv, SWF, mpeg-1, mpeg-2, VCD, SVCD, DVD, etc.) and Audio format(AC3, AAC, MP2, MP3, MP4, RA, WMA, etc.).
There is a similar question here,you can check the answer,hope it helps.
If i rent a movie from iTunes can i put it on my iPod?
http://answers.yahoo.com/question/?qid=20080427210350AAxOq3G