http://androidforums.com/eris-all-t...ated-links-updated-oct-1-2010-4-44pm-est.html

^Read that^ - Root your phone

http://androidforums.com/eris-all-things-root/204673-best-eris-rom.html

^not necessary, but read post number 2(choose a rom)^
(i suggest KaosFroyo)

http://androidforums.com/eris-all-things-root/199047-rooting-eris-wireless-tethering.html

^then read this^

 

or if you dont want to root, you can tether with easytether or pda net (both in the market)

 

Just download PDAnet from the market and plug the phone into your computer for tethering. That way you keep the battery charged at the same time. WiFi hotspot will only chew the battery. If you root, save the wifi hotspot for when you don't have a cable handy.

 

If you root you can also download wired tether which is also completely free. All you need are the drivers (which you install when you download HTC Sync).

 

No help here. Needlink to flash ROM.