1) I have yet to find a miniature access point (like a pen drive). The only thing that I could think of is if your firewall is computer-based (i.e. Symantec Enterprise Firewall, Linux, etc.) you could attach a USB wireless adapter to a USB port, and use ControlAP
to turn the box into an AP also. From the firewall perspective, it would just be another ethernet port.
Additionally, depending on if you already know what firewall you're using or not, you could select a wireless router that has a built-in firewall.It may not have the same features as a robust firewall (i.e. Cisco Pix), but it works for a lot of small environments.
2) Power over Ethernet (PoE) is also known as 802.3af. It delivers power over the unused pairs of ethernet to the wireless equipment. Your normal ethernet traffic will ride over the same cable without being affected. Additionally, this is wonderful for an installation where the equipment is in a ceiling 300 feet away, and there's no power around.
HTH. If you need any pricing on wireless routers or equipment, feel free to contact us