While our 5620 has a front switch and light for Bluetooth, the actual module is not installed. Supposedly you can get one from Acer themselves... but be prepared to pay a small fortune. And know the part number. And likely have it shipped overseas.
There's two options for adding Bluetooth. If you're going to wait for overseas shipping anyway, why not buy a cheap ($6.99) little low-profile USB bluetooth adapter from DealExtreme
(which works fine under both Windows and Mac). It takes awhile to arrive, but the one I got was cheap and works great. Best of all you don't have to crack your laptop open.
Oh, not scared of taking apart your Acer? Okay then. Roughly under the mousepad on the top of the motherboard is a small four-pin plug. If you can find a small plug to fit it, and are decent with a soldering iron, then you can modify a USB Bluetooth adapter to fit here. An easier way is to buy this pre-made off eBay for about $25. Just do a search for "acer bluetooth," and make sure the plug has a four-pin.
Why do you need Bluetooth? You don't. But it can be nice for transferring file to and from your cellphone, or using a wireless mouse. Plus it makes that switch on the front of your laptop actually do something!
The Wifi card is an Intel 3945 802.11a/b/g Mini-PCIe (PCI Express) card. It works just fine, but eventually you could switch to an 802.11n one to match your newer router if you wish. I ended up swapping mine out with a spare 802.11b/g Atheros card from a junk Toshiba for my own reasons; the good news is, there's no Bios whitelist issue that stops other cards from working.