Smuggle in to where? Getting something past the town gate guards is going to be considerably easier than getting strip-searched while being booking into prison.
For most situations, it'll probably be easier to convince the guards to allow you to bring in contraband rather than try to sneak it past them. Bribery, persuasion, deception (you wouldn't deprive an old man his walking stick), etc. Maybe you could even forge some kind of appropriate documentation - the Forgery skill is only contested by Forgery, which few people are trained in.
In any case, you may be interested in reading Complete Scoundrel. It has rules for creating smuggling compartments and that kind of thing.
The 2nd level Assassin spell Absorb Weapon lets you magically conceal a light weapon under your skin. The only way I can think of to count a bow as a light weapon is to make it Elvencraft (counts as a club), then make it 1 size category too small. Convoluted, but workable.