ems275, here's what I finally worked out via trial and error from deezmfnutz' instructions.
Do NOT use forwarding in Gmail. Make sure it's off.
Create a new filter and put "in:inbox" in the "Has the words" text box. Click next step, and IGNORE the pop-up telling you it won't work. Check the box labelled "forward to" and type in your BB mail address (as Deez pointed out, it'll be
, where xxx = your username and yyy = your provider abbreviation)
Create another filter in Gmail with whatever your sent from address is IN YOUR BB MAIL OPTION...by default, it'll be the
address, but I have changed mine to my gmail address. So, I put "firstname.lastname@example.org" in the "From" text box of my new filter, AND THEN (unfortunately, I think) you have to put your BB mail sig. (Sent from Verizon Wireless Blackberry, for example) in the "Has the words" text box. I had to do this to keep the mail I sent from my BB separate from the regular Gmail I sent...So, make sure the sig. you use in your BB mail is the same text you put in the "Has the words" box.
Click Next step, and check the "Skip Inbox" AND "Apply the Label" boxes...use a label like deez suggested, "Blackberry Sent"
Click Update Filter and you should be good to go...
(You can, I suppose, eliminate the sig. steps in the second filter and just keep up with the sent mail folder in Gmail...basically I just want to keep those in my account, so I might change my second filter to remove the sig.)