similar alternatives would be to

1) time strech your vocals a bit.

or

2) serach around the intrnet for a 'phone' or 'megaphone' effect vst. i only have it as harware so dont know a similar vst.

oo also there is a free wave editor called "GoldWave" which has a really good effect called 'mechanize' which is adjustable which may help you out.

cheers,
gil