I have the same homegrown bookkeeping software which I've used for forever. (Don't do this folks. Use Quickbooks. The only reason I use the homegrown stuff is because it publishes stats direct to my website.) I have a VA in the Philippines who I hired through Pepper. Every month or two, I take all of my credit card statements, zip them up, and send them to her. We have a standing orders document (terribly out of date -- should fix that) of what expenses count as business expenses and how to categorize them in the bookkeeping software. (Expenses are the only part which requires manual entry -- my sites do their own revenue tracking.)

There's a workflow hack or two to ensure that novel transactions get checked by me, eventually. (e.g. I have a personal credit card in the mix, for those rare times when both business cards fail, which means she sees a lot of transactions which aren't business related and should filter them all out. It wasn't obvious from the one-line description that e.g. my wedding venue is probably not appropriate for deduction, but since it was marked as novel (and ginormous relative to my expected expenses for that month), I caught it prior to doing the year in review numbers.

I do a more in-deoth review of the big expense categories (AdWords and travel) prior to doing my taxes and spot-check everything else. If e.g. a $60 software purchase ends up getting missed that's unfortunate, but it is only about ~$20 of unfortunate, and a few slip-ups are substantially cheaper in opportunity cost (and sanity) that having me do line-by-line review of all ~500 entries.

For general advice on how to work with VAs, I strongly recommend Rob Walling's book and have heard good things about the 4 Hour Work Week (but have never read it).