The best replacement for tethering is hotspot.

The best alternatives to tethering are rated as following:
★★★★★  hotspot
★★★★  mifi
★★★  mobile broadband
★★  personal hotspot
★★  aircard
★★  dongle
★  wifi
★  hotspot verizon
★  wifi direct
★  mobile hotspot
★  wifi hotspot
★  usb modem
  mobile ap
  hot spot
  mobile hot spot
  personal hotspots
  bluetooth tethering
  usb dongle
  air card
  phone as modem
  wireless tethering

Your alternative for tethering is not listed? Suggest!
Speaking about tethering, one probably shouldn't forget about iphone.

Other search terms related to tethering and their ratings are:

★★★★★ iphone
★★★ data plan
★★ blackberry
★★ hotspot
jailbreak iphone 4
mobile hotspot
You have in mind a companion for tethering and it is not yet here? Propose!

Google Trends

Scale is based on the average worldwide traffic of tethering in all years. Click on graph for more.