I use BIS and I have my BB set up to receive my Gmail through the automatic pop settings. I also use Outlook with pop for my gmail.

The problem that I'd like to resolve is that I hate having to delete emails twice; that is, deleting e-mails on my BB and then redeleting on Outlook or Gmail on the internet. If I set everything up to IMAP, will I be able to do this?

Thanks for your time.

On your BB there is a setting for your mail to ask you if you want to delete it from your handheld only, or you email box and handheld. Activate that setting. When you tell the BB to delete it from your device and mailbox it will do that.

deleting (on mailbox) via the default gmail (pop) interface will actually delete the message.

if you "delete on mailbox" via the imap setup, the message will archive in gmail (and will take a while to sync up)...

I also am trying to use Gmail IMAP on my 8800 and am having to delete twice. If I read mail on the BB and delete it, it archives it on Gmail web interface. Excellent!
But if I read it / archive it on the Gmail web interface, my BB still shows it.
Is this a sync issue? A settings issue? I have it set to synchronize deletes between my BB and mailbox.

Not a settings issue on your end...
its a product of the gmail-imap-bis setup, and that's just the way it works...

ive found that _eventually_ the changes sync up both ways...

When you say, "eventually", how long do you mean? Minutes, hours, or days?