jwolthuis - 12:41 pm on May 12, 2011 (gmt 0)
We use the free USPS Carrier Pickup every day to ship a dozen or so packages, all with "Tracking Numbers" (they no longer label them as "Delivery Confirmation").
Their 1st Class Parcel rates are hard to beat (13 ounces or less), and with a SCAN Form (PS Form 5630), our carrier can scan one barcode to accept all packages, so that customers can see when their package was picked-up.
Carrier Pickup must be requested online at usps.com in advance, but you can schedule an entire months-worth of pickups at the same time.
Compared to UPS, I avoid the daily-pickup fee, no fuel surcharges, and no magical "weight adjustments" appearing on my bill.