http://en.wikipedia.org/wiki/BASIC

FreeBASIC http://www.freebasic.net/

QB64 http://qb64.net/

RFO BASIC http://laughton.com/basic/

BrowserBASIC http://pewtersoftware.com/browserbasic/

FNXBasic http://fnxbasic.com/

GAMBAS http://gambas.sourceforge.net/

RapidQ http://rapidq.phatcode.net/

Panoramic http://panoramic-language.pagesperso-orange.fr/

VB.net

NaaLaa http://naalaa.com/

CoolBASIC http://www.coolbasic.com/index.php?lang=en

Jabaco http://jabaco.org/

BASIC4GL http://www.basic4gl.net/

DarkBASIC http://www.thegamecreators.com/?m=view_product&id=2000&page=free

BlitzBASIC http://www.blitzbasic.com/Products/_index_.php

BCX http://bcxbasic.com/

Brutus2D http://brutus.pewtersoftware.com/

GFA-BASIC http://gfabasic32.blogspot.com/

XBASIC http://www.xbasic.org/

XBLite http://www.xblite.com/

OxygenBASIC http://www.oxygenbasic.org/

ThinBASIC http://www.thinbasic.biz/projects/thinbasic/thinBasic_1.8.9.0.zip

others http://basic.mindteq.com/

Learn: http://petesqbsite.com/