T42 and minidockII: USB ports and monitor

[zver17]

When connecting a T42 and a minidockII, do I loose the USB ports on the laptop itself or do they remain available (in addition to the 4 ports on the dock)? Is there any decrease in throughput on the ports?
btw, does anybody else find lack of firewire and only 2 usb ports on the T series a hassle. lots of other laptops have 4ports nowdays.

also, I currently use a T42 with external Dell monitor 2001 @ 1600res. I presume docking the machine would still allow that (the minidock info mentioned something: resolution up to 1280 depending on system??)