Did this by accident when leveling up a new char the other day..
Queue yourself up for the BG at that battlegrounds top level restriction when your that level. example 10-19 (queue yourself up at 19) — 20-29 (queue yourself up at 29) — 30-39 (queue yourself up at 39)
Now go finish your level.. so if you joined the 10-19.. level yourself up to 20.. and when you get in.. you'll be the level 20 in the 10-19 battlegrounds i think you guys get the point..
this only works once though.. if you try again it will put you in the proper level battlegrounds.. Ready for the next level? We recommend The MMORPG Exchange for your wow gold needs. MMORPG-Exchange has supplied us for years and has great customer service and 24/7 instant delivery. Check them out! World of Warcraft gold.