here uyou go:
Dell Optiplex GX620 WiFi Half Height PCI Wireless Card
Dell Optiplex GX620 Wireless Adapter
Based on Wireless N technology, up to 3 times faster than 802.11g.
Fully compatible with 802.11b/g/n network devices
Specifications:
Standards: IEEE 802.11b / g / n
Interface: 32 Bit PCI
Security: WPA2/WPA-PSK (TKIP & AES), WEP 64/128-bit, CCX
http://www.discountelectronics.com/product?product_id=16615&product_model=3