With good performance and a complete range of connectivity options, the new thin-and-light Latitude D620 will keep you in business when you're away from the desk

Specifications

Operating System
Genuine Windows® XP Professional
Enjoy the benefits of SP2 - Service Pack 2
Dell offers systems which run Genuine Windows®  XP and are capable of running Genuine Windows®  VistaTM . For more details on Dell systems that can run Genuine Windows® VistaTM
Learn More About Operating Systems

Memory
Dual Channel DDR2 Shared Memory
DDR2 is a memory architecture that enables systems to improve performance and reduce power consumption. The amount of RAM you have determines how many programs can be executed at one time and how much data can be readily available to a program.
Available DIMM Slots:
Two Memory slots offering up to 4GB
Memory Bandwidth:
667MHz - 8.5 GB/s with dual channel - Improves performance
Performance Professional User:
2GB or more for Intensive simultaneous business applications with headroom for future OS/Applications
Mainstream User:
1GB or more is recommended for business users running multiple simultaneous office applications
 Learn More About DDR2 Memory

Graphics
256MB NVIDIA®  Quadro NVS 110M TurboCacheTM
The 256MB NVIDIA Quadro NVS 110M offers all the latest graphics technology to produce extraordinary visual effects, robust wide-aspect LCD support and compatibility with all major business applications.
Intel®  Graphics Media Accelerator 950 (Up to 224MB shared)
The GMA 950 graphics core is an intelligent and responsive graphics engine built into the chipset that is on the motherboard. This integration provides incredible visual quality, faster graphics performance and flexible display options.

Displays
WXGA+ (1440 x 900 resolution) WXGA (1280 x 800 resolution)

Hard Drives
SATA - also known as Serial ATA
Benefits of the SATA drives offered on Latitude notebooks: Password protection feature on the HDD. A password must be entered before the HDD can be accessed and the system boots. This provides an extra layer of data security.
Faster, Improved data integrity, and Improved scalability
Capacities up to 120GB1

Additional Features
POWER:
Power Supply:
65 Watt or 90 Watt AC adapter with cord wrapping
Batteries featuring ExpressChargeTM :
Primary 4-cell/35 WHr
Primary 6-cell/56 WHr
Primary 9-cell/85 WHr
Secondary 6-cell/48 WHr "Smart" Li-Polymer battery 
CONNECTIVITY:
Wired:
Wired: 56K v924 Internal Modem 10/100/1000 Gigabit Ethernet2 network interface adaptor
WLAN
Intel®  3945 WiFi 802.11a/g, Dell Wireless 1390 802.11g, Dell Wireless 1490 802.11a/g Dual-Band Mini-Cards, Internal Bluetooth (optional).
EXPANDABILITY:
PC Card:
One Type I or Type II
I/O Ports:
Serial, docking connector, 4 USB, VGA, headphone/speaker out, infrared port, RJ-11, RJ-45, AC power, integrated microphone , infrared
Docking:
D/Port, D/Dock, D/View Notebook Stand, D/Monitor Stand
Modular Options:
24X CD-ROM, 8X DVD+/-RW3, 24X CDRW/DVD4, Floppy Disk Drive
USB Memory Keys:
128MB, 256MB7 and 512MB USB Memory Keys (optional) 
SECURITY:
Physical Security:
Cable Lock Slots, Media Module and Hard Drive Locks.
User & System Security:
Integrated Smart Card Reader, Trusted Platform Module 1.2 and optional UPEKTM  finger print reader. Wave EmbassyTM  Trust Suite by Wave Systems security software.
Network Security:
802.11 WiFi Protected Access (WPA), 802.11i (WPA2), Virtual Private Networks (VPN) and 802.1x with EAP modes

Review

Pros:Dual Core is very fast, good battery life, soft keyboard, feature rich, generally quiet
Cons:Adjusting to lower screen brightness creates a buzzing noise which can get annoying.

Source:
http://reviews.cnet.com