I'm using a lot of effects on vocals, but had my first gig last week and had to do without them due to serious feedback problems. Amongst other things I'm using a lot of delay, and some effects which boost narrow frequencies. If it helps to have a listen, you can go here - http://www.mp3unsigned.com/Showband.asp?id=18239

Any help would be very appreciated

!!!!! Sounds like you are trying to get that "New Vaudeville Band" singing through a megaphone sound.

You have hit the nail on the head all by yourself, ol` son.
Just about everything you are doing is going to generate frewuencies in the upper mid and treble range which is the area most prone to feedback, and then you have it heavily compressed!.

Unless you are trying to appeal to an audience of bats, have you considered easing up on the quirky vocal eq & effects?

A flutter echo on a snare part is a sure recipe for disaster live.(second track)

Just my take on it, but I found it all rather irritating and distracting.
Suspect a more conventional approach might get people to listen longer.

Failing that if you are determined that this shall be Your Sound, you need a BIG EXPENSIVE P.A. and someone who knows what they are doing to mix you.

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Me? But I`m such a loveable old bugger!

Are you putting the effected sound through the foldback? Most feedback comes from the foldback speakers rather than the FOH speakers so if you can arrange it so that you get a 'normal' vocal coming through the foldback and the effected sound through the main PA this should help. You may need to split your mic signal into two channels to do this - which should allow you to run a low level of effected signal into the foldback as well just to help you get an idea of what's going on out front.

You may also need to treat your recorded and live effects as two different beasts. Maybe find some other effects that approximate the recorded versions but which don't use such high boosting of frequencies. Cut unwanted frequencies rather than boost the wanted ones. Sounds like you are using some resonant filter effects (my old Quadraverb has a similar setting) or ring modulation. Rather than use a 100% wet signal, try a mix with a lot more dry signal. Push it as much as you can before feedback occurs and then back the effect off a notch or two.

As Ivan said, avoid compression if you can - and again use it just on the FOH mix and not the foldback.

If you really need to hear all the effect when performing, then get an in-ear monitoring system. If you don't move about much, then a hardwired one will do quite happily and won't cost much to put together. Behringer or Samson headphone amp and some earbud earpieces, then feed it from the aux send(s) on the mixer that would normally feed the foldback. You may need to put up an ambient mic or two (just for the foldback mix) so you can hear what else is going on.

Hmm, this was quite a small stage, there was no foldback at all but I was pretty much on top of the FOH speakers anyway. I've performed there before and had no problems, but doing a more standard solo acoustic or indie band. Since there's only me, my guitar and my laptop, I just feed everything including a metronome into an earphone for me to follow. I'll try it without the compression though, I'd forgotten about that.