I found this domain name, myself, about 4 days ago and was tempted to register it. Try a search on google and you'll see that it doesn't seem to get great numbers. The plural possibilities are also very unsatisfactory -- as the 50,000+ search total could be a combination of lyricstosong.com, lyricstosongs.com, lyrictosong.com, or lyrictosongs.com (with any one of them being responsible for the search volume). Also, I couldn't see the potential "type-in" value of this domain name. I wasn't enthused with it so I passed it by.
By the way, I'm not trying to discourage you. I'm just giving you my opinion on "why" I passed it by.
me 3. Hardcores type "LYRICS" and newbies may type "WORDS" but LYRICTOSONG would be worth only if you had an idea that couldn't wait and this was the best name you could get for that type of site. Perhaps a poets' or lyric writers' forum who offer words to other people's music (or vice versa)