I consider it was enough having a slow cell phone and space wasted because of all the extra apps that "Telcel" adds to the modified roms installed by them to the cell phones, I did a lot of research about how to install CyanogenMod 7 on my LG P500h.
http://sensblogg-evolivet.blogspot.mx/2011/09/si-tienes-el-lg-optimus-one-p500-yo.html (This blog explains in detail (almost) everything I did.
Plus, this is a (long?) list of other links I found:
http://forum.xda-developers.com/showthread.php?t=810271 (To download KDZ_FW_UPD this worked to rescue/install telcel ROM updated)
http://www.lgmobile.cl/foro-comunidad/lg-mobile/descarga-el-pc-suit-de-lg/descarga-lg-pc-suite-4
http://htcero.com/2012/02/como-instalar-cyanogenmod-7-en-el-lg-optimus-one-p500/
http://www.chileandroid.com/t6251-ayuda-se-me-quedo-pegado-el-celular-en-el-logo-lg
http://mioptimusone.blogspot.mx/2011/03/como-volver-al-estado-de-fabrica.html
http://www.taringa.net/posts/linux/13511190.R/LG-P500h-android-gingerbread-2_3_3-Original-telcel-mexico.html
http://www.chileandroid.com/t1800-rom-telcel-lg-optimus-one-p500h
http://www.chileandroid.com/t1896p60-repositorio-links-para-el-lge-p500-p500h-optimus-one
http://www.cyanogenmod.com/devices/lg-optimus-one
http://download.cyanogenmod.com/?type=stable&device=p500
http://www.itbarna.com/como-hacer-un-nandroid-backup-en-android
http://mioptimusone.blogspot.mx/2011/07/repositorio-links-para-el-lge-p500p500h.html
http://adf.ly/1Xb2u (To download Gingerbreak, works with Android 2.2, not with 2.3)
http://webtrickz.com/guide-to-install-android-2-3-4-gingerbread-custom-rom-on-lg-optimus-one-step-by-step-instructions/2/
http://foro.mexdroid.com/index.php?topic=903.0 (The explanation helped me to "root" using superoneclick for Android 2.3)
http://developer.android.com/sdk/index.html (To "root" Android 2.3)
http://androidflip.com/how-to-root-lg-optimus-one-p500-android-2-3-3-gingerbread/
http://www.techofweb.com/technology/root-android-gingerbread-gingerbreak.html (Works for Android 2.2)