You can always play around with the free to play version of Singstar, though you might have to pony up for a song or two. It allows the PlaystationEye to be used as a mic. Other details you might be interested in about the game according to Wikipedia:
SingStar USB microphones
The SingStar games require SingStar-branded microphones – one red and one blue – which connect to the PlayStation console via a single USB converter. The USB converter was required so that both microphones would use a single USB port; the PlayStation 2 and later versions of the PlayStation 3 only have two USB ports, and the second port needed to remain free for camera functionality. The PlayStation 2 Headset was originally considered as an alternative to microphones, however the headset was not technically sufficient, and London Studio felt that handheld microphones were important to the authentic experience.
Wireless microphones, with a 2.4 GHz receiver attached to the PS2 or PS3 by USB, became available in Europe in March 2009. Bluetooth microphones were originally planned to launch with the PS3 version of SingStar, but running two Bluetooth microphones together was found to be difficult, so the PS3 game launched with the same USB microphones as the PS2 game.
The microphones detect pitch using digital signal processing, which analyses the frequency of the incoming signal via Fast Fourier transform. The frequency is then compared to stored information to evaluate if the note is correct. Regular singing segments do not feature speech recognition, and so humming into the microphones at the correct pitch will also score points. Rap sections use a combination of speech recognition and rhythm detection.
Tracks on the original SingStar for PlayStation 2 were mixed from master records, which allowed the artist's voice to be completely removed from the song. This feature was dropped in subsequent games because the requirement for master tracks would have restricted the studio's choice of songs. SingStar for PlayStation 3 introduced the ability to digitally suppress vocals, using ADRess (Azimuth Discrimination and Resynthesis) technology developed by Dan Barry at the Audio Research Group, based in the Dublin Institute of Technology. The ADRess settings vary for each track, and the technology is able to successfully remove the vocal tracks from 80% of songs.
The PlayStation 3 version also includes various VST plugins developed by Sound Forge, adapted to run natively on the console. The input signal undergoes a vocal signal chain which includes high-pass filter, wave hammer compressor and a reverb with a 1.2 second decay. Users are able to control the audio processing during playback, adding features such as pitch shifting.
According to the listing in the PSN store for the free-to-play version, wireless headsets work as mics as well. https://store.sonyentertainmentnetwork.com/#!/en-us/cid=UP9000-NPUA80756_00-SINGSTARPS3V0100?utm_medium=email&utm_source=webstore&utm_campaign=130128&utm_content=sentemplate&utm_medium=&utm_source=&utm_campaign=&emcid=CHI000004
Though I'm not sure this feature is available (backwards patched) for the various older disc versions of Singstar.Edited by Zookster - 10/4/13 at 10:56am